feat(tools): add 'Gantt by Unit' tab to deployment history

Third view on /tools/deployment-history.  Where 'Gantt by Project' has
one row per project showing that project's deployments, 'Gantt by Unit'
inverts it — one row per seismograph, bars colored by the project the
unit was deployed to.

The natural use case: "where has BE11529 been across all my jobs?"
Spotting unit rotation patterns, idle gaps, and concurrent assignments
gets immediate visually.

Service
- deployment_history.get_deployment_history_data() now also returns a
  `units` array.  Each unit dict carries:
    {id, bars[], first_active, assignment_count, any_active}
  Each bar has the project_name + project_color baked in so the
  renderer can paint by job without a second lookup.
- Units sorted: currently-active first, then by first_active ascending.

UI
- Third tab "Gantt by Unit" added next to Calendar / Gantt by Project.
- Tab switcher refactored to a small registry (_DH_TABS) so adding more
  views in the future is a one-line addition.
- URL hash sync now supports #gantt and #byunit; nav buttons preserve
  the active tab across month-paging.
- SVG layout: 160px label gutter (smaller than the project Gantt's
  220px since unit IDs are short), 32px row height, green dot for
  units with at least one active deployment.  Unit ID is clickable
  → /unit/{id}; each bar is clickable → /projects/{p}.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

backend/main.py

@@ -109,6 +109,9 @@ app.include_router(watcher_manager.router)
 from backend.routers import admin_modules
 app.include_router(admin_modules.router)
 
+from backend.routers import deployment_history
+app.include_router(deployment_history.router)
+
 # Projects system routers
 app.include_router(projects.router)
 app.include_router(project_locations.router)

backend/routers/deployment_history.py

@@ -0,0 +1,99 @@
+"""
+Fleet-wide deployment-history calendar — Phase 2 of the
+deployment-history visualisation work (Phase 1 is the per-unit Gantt
+on /unit/{id}).
+
+Renders all UnitAssignment windows across all projects on a 12-month
+calendar grid styled like the Job Planner.  Each day cell shows one
+mini-bar per project that had ≥1 active assignment that day.  Click a
+day → side panel with the (unit, location) pairs active.
+
+Routes:
+  GET  /tools/deployment-history              — HTML page
+  GET  /api/admin/deployment-history/day      — JSON list of deployments
+                                                 on a specific date (used
+                                                 by the day-detail panel)
+"""
+
+from __future__ import annotations
+
+from datetime import date, datetime
+from typing import Optional
+
+from fastapi import APIRouter, Depends, Query, Request
+from fastapi.responses import HTMLResponse, JSONResponse
+from sqlalchemy.orm import Session
+
+from backend.database import get_db
+from backend.services.deployment_history import (
+    get_deployment_history_data,
+    get_deployments_on_day,
+)
+from backend.templates_config import templates
+
+router = APIRouter()
+
+
+@router.get("/tools/deployment-history", response_class=HTMLResponse)
+def deployment_history_page(
+    request: Request,
+    year:  Optional[int] = Query(None),
+    month: Optional[int] = Query(None),
+    db: Session = Depends(get_db),
+):
+    """Fleet-wide deployment history calendar.
+
+    Defaults to a 12-month window ending in the current month (so the
+    operator sees the recent past, not the future).  ?year=&month= can
+    override the START of the window to scroll backward or forward.
+    """
+    today = date.today()
+    # Default: 12-month window ending this month → start = 11 months back.
+    if year is None or month is None:
+        # 11 months back from current month.
+        m = today.month - 11
+        y = today.year
+        while m < 1:
+            m += 12
+            y -= 1
+        start_year, start_month = y, m
+    else:
+        start_year, start_month = year, month
+
+    calendar = get_deployment_history_data(db, start_year, start_month)
+
+    # Build prev/next navigation values.
+    prev_y, prev_m = (start_year - 1, 12) if start_month == 1 else (start_year, start_month - 1)
+    next_y, next_m = (start_year + 1, 1) if start_month == 12 else (start_year, start_month + 1)
+
+    return templates.TemplateResponse("admin/deployment_history.html", {
+        "request":  request,
+        "calendar": calendar,
+        "today":    today.isoformat(),
+        "prev_year":  prev_y,
+        "prev_month": prev_m,
+        "next_year":  next_y,
+        "next_month": next_m,
+    })
+
+
+@router.get("/api/admin/deployment-history/day")
+def deployment_history_day(
+    target_date: str = Query(..., description="YYYY-MM-DD"),
+    db: Session = Depends(get_db),
+):
+    """Return assignments active on a specific calendar day."""
+    try:
+        d = date.fromisoformat(target_date)
+    except ValueError:
+        return JSONResponse(
+            {"error": f"Invalid date: {target_date!r}"},
+            status_code=400,
+        )
+
+    deployments = get_deployments_on_day(db, d)
+    return JSONResponse({
+        "date":        target_date,
+        "count":       len(deployments),
+        "deployments": deployments,
+    })

backend/services/deployment_history.py

@@ -0,0 +1,387 @@
+"""
+Deployment-history calendar service — builds the data structure for the
+fleet-wide deployment-history grid (`/tools/deployment-history`).
+
+For each calendar day in a 12-month window, computes which projects had
+at least one unit assigned to a location on that day.  Renders as
+multi-month grid (job-planner style) with project-colored bars per day.
+
+Distinct from `services/fleet_calendar_service.py` which renders
+forward-looking RESERVATIONS for the planner.  This one is purely
+historical / current — it walks `unit_assignments` instead of
+`job_reservations`.
+"""
+
+from __future__ import annotations
+
+import hashlib
+from datetime import date, datetime, timedelta
+from calendar import monthrange
+from typing import Optional
+
+from sqlalchemy.orm import Session
+from sqlalchemy import and_, or_
+
+from backend.models import Project, UnitAssignment
+
+
+# Color palette for projects without an explicit color attribute.  Chosen
+# to have decent contrast on both light and dark backgrounds; cycles
+# deterministically by SHA1(project_id).
+_PROJECT_COLOR_PALETTE = [
+    "#f48b1c", "#142a66", "#7d234d", "#0e7490", "#15803d",
+    "#a16207", "#9333ea", "#dc2626", "#0d9488", "#1d4ed8",
+    "#be185d", "#65a30d", "#0891b2", "#7c3aed", "#b91c1c",
+]
+
+
+def _color_for_project(project_id: str) -> str:
+    """Deterministic color assignment from a fixed palette."""
+    h = hashlib.sha1(project_id.encode("utf-8")).digest()[0]
+    return _PROJECT_COLOR_PALETTE[h % len(_PROJECT_COLOR_PALETTE)]
+
+
+def _month_short(m: int) -> str:
+    return ["Jan", "Feb", "Mar", "Apr", "May", "Jun",
+            "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"][m - 1]
+
+
+def _month_full(m: int) -> str:
+    return ["January", "February", "March", "April", "May", "June",
+            "July", "August", "September", "October", "November", "December"][m - 1]
+
+
+def get_deployment_history_data(
+    db: Session,
+    start_year: int,
+    start_month: int,
+) -> dict:
+    """
+    Build the calendar data structure for a 12-month window starting at
+    (start_year, start_month).
+
+    Returns:
+        {
+          "months": [
+            {
+              "year": int,
+              "month": int,            # 1-12
+              "name": "January",
+              "short_name": "Jan",
+              "year_short": "26",
+              "num_days": int,
+              "first_weekday": int,    # 0=Mon..6=Sun (datetime.weekday())
+              "active_days": {
+                  day_num: [project_id, project_id, ...]  # projects with
+                                                          # ≥1 active assignment
+                                                          # on that day
+              },
+            },
+            ...                                          # 12 entries
+          ],
+          "projects": [
+            {
+              "id": str,
+              "name": str,
+              "color": str,
+              "status": str,
+              "client_name": str | None,
+              "assignment_count": int,    # total assignments contributing to
+                                          # this 12-month window
+              "first_active":   "YYYY-MM-DD" | None,
+              "last_active":    "YYYY-MM-DD" | None,
+            },
+            ...                                          # only projects with
+                                                         # ≥1 assignment in the
+                                                         # window, sorted by
+                                                         # first_active ASC
+          ],
+          "total_assignments": int,
+          "total_active_units": int,    # distinct unit_ids across the window
+          "window": {
+              "start_year": int,
+              "start_month": int,
+              "end_year": int,
+              "end_month": int,
+              "first_date": "YYYY-MM-DD",
+              "last_date":  "YYYY-MM-DD",
+          },
+        }
+    """
+    # Compute window edges.
+    first_date = date(start_year, start_month, 1)
+    # 12 months → end on day-1 of (start + 12)
+    end_year  = start_year + ((start_month + 10) // 12)
+    end_month = ((start_month + 10) % 12) + 1
+    last_date = date(end_year, end_month, monthrange(end_year, end_month)[1])
+
+    now = datetime.utcnow()
+
+    # Fetch every assignment that overlaps the window.  An assignment
+    # overlaps if assigned_at <= last_date AND (assigned_until is NULL
+    # OR assigned_until >= first_date).
+    assignments = (
+        db.query(UnitAssignment)
+        .filter(UnitAssignment.assigned_at <= datetime.combine(last_date, datetime.max.time()))
+        .filter(
+            or_(
+                UnitAssignment.assigned_until == None,   # noqa: E711 — active
+                UnitAssignment.assigned_until >= datetime.combine(first_date, datetime.min.time()),
+            )
+        )
+        .all()
+    )
+
+    # Resolve referenced projects in one query.
+    proj_ids = {a.project_id for a in assignments}
+    proj_map = {
+        p.id: p for p in db.query(Project).filter(Project.id.in_(proj_ids)).all()
+    } if proj_ids else {}
+
+    # Resolve location names in one batch query (used by the Gantt view
+    # for per-bar tooltips).
+    from backend.models import MonitoringLocation
+    loc_ids = {a.location_id for a in assignments}
+    loc_name_map = {
+        l.id: l.name for l in db.query(MonitoringLocation).filter(
+            MonitoringLocation.id.in_(loc_ids)
+        ).all()
+    } if loc_ids else {}
+
+    # Compute "active days per project" by walking each assignment and
+    # adding every day in its [start, end] ∩ [first_date, last_date].
+    # O(N_assignments × avg_window_days); for a typical fleet this is
+    # bounded (hundreds of assignments × hundreds of days = manageable).
+    # Also collect raw per-assignment bar data for the Gantt view.
+    project_active_days: dict[str, set[date]] = {}
+    project_first_active: dict[str, date] = {}
+    project_last_active:  dict[str, date] = {}
+    project_assignment_count: dict[str, int] = {}
+    project_bars: dict[str, list[dict]] = {}
+    distinct_units: set[str] = set()
+
+    for a in assignments:
+        start = max(a.assigned_at.date() if a.assigned_at else first_date, first_date)
+        end_dt = a.assigned_until or now
+        end   = min(end_dt.date(), last_date)
+        if end < start:
+            continue
+        days = project_active_days.setdefault(a.project_id, set())
+        d = start
+        while d <= end:
+            days.add(d)
+            d += timedelta(days=1)
+        project_assignment_count[a.project_id] = project_assignment_count.get(a.project_id, 0) + 1
+        distinct_units.add(a.unit_id)
+        # Track first/last active dates in the window.
+        prev_first = project_first_active.get(a.project_id)
+        if prev_first is None or start < prev_first:
+            project_first_active[a.project_id] = start
+        prev_last = project_last_active.get(a.project_id)
+        if prev_last is None or end > prev_last:
+            project_last_active[a.project_id] = end
+
+        # Per-assignment bar data — used by the Gantt view's renderer.
+        # `is_active` reflects whether the assignment_until was still NULL
+        # at fetch time (open-ended deployment); the clipped `end` here
+        # is just for visual bar drawing.
+        project_bars.setdefault(a.project_id, []).append({
+            "unit_id":       a.unit_id,
+            "location_id":   a.location_id,
+            "location_name": loc_name_map.get(a.location_id, "(unknown location)"),
+            "start":         start.isoformat(),
+            "end":           end.isoformat(),
+            "is_active":     a.assigned_until is None,
+            "source":        a.source,
+        })
+
+    # Build the projects array (sorted by first_active ascending so the
+    # legend reads in deployment-order).
+    projects_data = []
+    for pid, days in project_active_days.items():
+        p = proj_map.get(pid)
+        if not p:
+            # Assignment references a deleted project — surface it anyway
+            # with a placeholder name, since the bars still need a label.
+            projects_data.append({
+                "id": pid,
+                "name": "(deleted project)",
+                "color": _color_for_project(pid),
+                "status": "deleted",
+                "client_name": None,
+                "assignment_count": project_assignment_count.get(pid, 0),
+                "first_active": project_first_active[pid].isoformat() if pid in project_first_active else None,
+                "last_active":  project_last_active[pid].isoformat()  if pid in project_last_active  else None,
+                "bars":         project_bars.get(pid, []),
+            })
+            continue
+        projects_data.append({
+            "id":     pid,
+            "name":   p.name,
+            "color":  _color_for_project(pid),
+            "status": p.status or "active",
+            "client_name":      p.client_name,
+            "assignment_count": project_assignment_count.get(pid, 0),
+            "first_active":     project_first_active[pid].isoformat() if pid in project_first_active else None,
+            "last_active":      project_last_active[pid].isoformat()  if pid in project_last_active  else None,
+            "bars":             project_bars.get(pid, []),
+        })
+
+    projects_data.sort(key=lambda p: (p["first_active"] or "9999", p["name"]))
+
+    # ── Per-unit view data (Gantt-by-Unit tab) ────────────────────────
+    # Same source assignments, re-grouped by unit_id.  Each bar carries
+    # the project's color + name so the renderer can paint by job
+    # without doing a second lookup.
+    unit_bars: dict[str, list[dict]] = {}
+    project_lookup = {p["id"]: p for p in projects_data}
+    for a in assignments:
+        start = max(a.assigned_at.date() if a.assigned_at else first_date, first_date)
+        end_dt = a.assigned_until or now
+        end   = min(end_dt.date(), last_date)
+        if end < start:
+            continue
+        p_info = project_lookup.get(a.project_id, {})
+        unit_bars.setdefault(a.unit_id, []).append({
+            "project_id":    a.project_id,
+            "project_name":  p_info.get("name", "(deleted project)"),
+            "project_color": p_info.get("color", _color_for_project(a.project_id)),
+            "location_id":   a.location_id,
+            "location_name": loc_name_map.get(a.location_id, "(unknown location)"),
+            "start":         start.isoformat(),
+            "end":           end.isoformat(),
+            "is_active":     a.assigned_until is None,
+            "source":        a.source,
+        })
+
+    # Sort units by first-active date so the most-recently-deployed
+    # units sit at the top.  Reverse if we want oldest-first.
+    units_data = []
+    for uid, bars in unit_bars.items():
+        bars.sort(key=lambda b: b["start"])
+        first_start = bars[0]["start"]
+        # "active now" flag = any bar is still active
+        any_active = any(b["is_active"] for b in bars)
+        units_data.append({
+            "id":              uid,
+            "bars":            bars,
+            "first_active":    first_start,
+            "assignment_count": len(bars),
+            "any_active":      any_active,
+        })
+    units_data.sort(key=lambda u: (not u["any_active"], u["first_active"], u["id"]))
+
+    # Now build the months array.
+    months_data = []
+    cur_year, cur_month = start_year, start_month
+    for _ in range(12):
+        num_days = monthrange(cur_year, cur_month)[1]
+        first_weekday = date(cur_year, cur_month, 1).weekday()   # 0=Mon..6=Sun
+        active_days: dict[int, list[str]] = {}
+        for day_num in range(1, num_days + 1):
+            d = date(cur_year, cur_month, day_num)
+            day_projects = [
+                pid for pid, days in project_active_days.items()
+                if d in days
+            ]
+            if day_projects:
+                # Sort by the project's color-stable order so bars don't
+                # jitter between days.
+                day_projects.sort()
+                active_days[day_num] = day_projects
+        months_data.append({
+            "year":         cur_year,
+            "month":        cur_month,
+            "name":         _month_full(cur_month),
+            "short_name":   _month_short(cur_month),
+            "year_short":   f"{cur_year % 100:02d}",
+            "num_days":     num_days,
+            "first_weekday": first_weekday,
+            "active_days":  active_days,
+        })
+        # Advance one month.
+        if cur_month == 12:
+            cur_year += 1
+            cur_month = 1
+        else:
+            cur_month += 1
+
+    return {
+        "months":   months_data,
+        "projects": projects_data,
+        "units":    units_data,
+        "total_assignments":    len(assignments),
+        "total_active_units":   len(distinct_units),
+        "window": {
+            "start_year":  start_year,
+            "start_month": start_month,
+            "end_year":    end_year,
+            "end_month":   end_month,
+            "first_date":  first_date.isoformat(),
+            "last_date":   last_date.isoformat(),
+        },
+    }
+
+
+def get_deployments_on_day(
+    db: Session,
+    target_date: date,
+) -> list[dict]:
+    """
+    Return the list of (unit, location, project) tuples that were
+    actively assigned on a specific calendar date.  Used for the
+    day-detail side panel when an operator clicks a day cell.
+    """
+    from backend.models import MonitoringLocation, RosterUnit
+
+    day_start = datetime.combine(target_date, datetime.min.time())
+    day_end   = datetime.combine(target_date, datetime.max.time())
+
+    rows = (
+        db.query(UnitAssignment)
+        .filter(UnitAssignment.assigned_at <= day_end)
+        .filter(
+            or_(
+                UnitAssignment.assigned_until == None,   # noqa: E711
+                UnitAssignment.assigned_until >= day_start,
+            )
+        )
+        .order_by(UnitAssignment.project_id, UnitAssignment.unit_id)
+        .all()
+    )
+
+    if not rows:
+        return []
+
+    loc_ids = {a.location_id for a in rows}
+    proj_ids = {a.project_id for a in rows}
+    loc_map = {
+        l.id: l for l in db.query(MonitoringLocation).filter(
+            MonitoringLocation.id.in_(loc_ids)
+        ).all()
+    }
+    proj_map = {
+        p.id: p for p in db.query(Project).filter(
+            Project.id.in_(proj_ids)
+        ).all()
+    }
+
+    results = []
+    for a in rows:
+        loc  = loc_map.get(a.location_id)
+        proj = proj_map.get(a.project_id)
+        results.append({
+            "assignment_id":   a.id,
+            "unit_id":         a.unit_id,
+            "location_id":     a.location_id,
+            "location_name":   loc.name  if loc  else "(unknown location)",
+            "project_id":      a.project_id,
+            "project_name":    proj.name if proj else "(deleted project)",
+            "project_color":   _color_for_project(a.project_id),
+            "assigned_at":     a.assigned_at.isoformat()    if a.assigned_at    else None,
+            "assigned_until":  a.assigned_until.isoformat() if a.assigned_until else None,
+            "is_active":       a.assigned_until is None,
+            "source":          a.source,
+        })
+
+    return results

templates/admin/deployment_history.html

@@ -0,0 +1,711 @@
+{% extends "base.html" %}
+
+{% block title %}Deployment History - Seismo Fleet Manager{% endblock %}
+
+{% block extra_head %}
+<style>
+.dh-calendar-grid {
+    display: grid;
+    grid-template-columns: repeat(4, 1fr);
+    gap: 1rem;
+}
+@media (max-width: 1280px) { .dh-calendar-grid { grid-template-columns: repeat(3, 1fr); } }
+@media (max-width: 768px)  { .dh-calendar-grid { grid-template-columns: repeat(2, 1fr); } }
+@media (max-width: 480px)  { .dh-calendar-grid { grid-template-columns: 1fr; } }
+
+.dh-month-card {
+    background: white;
+    border-radius: 0.5rem;
+    padding: 0.75rem;
+    box-shadow: 0 1px 3px rgba(0,0,0,0.1);
+}
+.dark .dh-month-card { background: rgb(30 41 59); }
+
+.dh-day-grid {
+    display: grid;
+    grid-template-columns: repeat(7, 1fr);
+    gap: 2px;
+    font-size: 0.75rem;
+}
+.dh-day-header {
+    text-align: center;
+    font-weight: 600;
+    color: #6b7280;
+    padding: 0.25rem 0;
+}
+.dark .dh-day-header { color: #9ca3af; }
+
+.dh-day-cell {
+    aspect-ratio: 1;
+    display: flex;
+    flex-direction: column;
+    align-items: stretch;
+    justify-content: flex-start;
+    border-radius: 0.25rem;
+    position: relative;
+    transition: all 0.15s ease;
+    font-size: 0.7rem;
+    padding-top: 2px;
+    background-color: #f3f4f6;
+    color: #374151;
+    cursor: pointer;
+}
+.dh-day-cell:hover {
+    transform: scale(1.1);
+    z-index: 10;
+}
+.dh-day-cell.empty {
+    background: transparent;
+    cursor: default;
+}
+.dh-day-cell.empty:hover { transform: none; }
+.dh-day-cell.today {
+    ring-color: #f48b1c;
+    font-weight: 700;
+    color: #b84a12;
+}
+.dark .dh-day-cell {
+    background-color: rgba(55, 65, 81, 0.5);
+    color: #d1d5db;
+}
+.dh-day-cell .dh-day-num {
+    text-align: center;
+    flex-shrink: 0;
+}
+.dh-day-cell .dh-bars {
+    display: flex;
+    flex-direction: column;
+    gap: 1px;
+    margin: 2px 2px 0 2px;
+}
+.dh-bar {
+    height: 3px;
+    border-radius: 1px;
+}
+</style>
+{% endblock %}
+
+{% block content %}
+<div class="mb-6 flex items-center justify-between flex-wrap gap-3">
+    <div>
+        <a href="/tools" class="text-sm text-seismo-orange hover:text-seismo-burgundy">← Back to Tools</a>
+        <h1 class="text-3xl font-bold text-gray-900 dark:text-white mt-1">Deployment History</h1>
+        <p class="text-gray-600 dark:text-gray-400 mt-1">
+            Where every unit has been — actual assignment windows, color-coded by project.
+            For future / planned deployments use the <a href="/fleet-calendar" class="text-seismo-orange hover:text-seismo-burgundy">Job Planner</a>.
+        </p>
+    </div>
+</div>
+
+<!-- View tabs: Calendar | Gantt (by project) | By Unit (gantt by unit) -->
+<div class="flex rounded-lg bg-gray-100 dark:bg-gray-700 p-1 mb-6 w-fit">
+    <button id="dh-tab-calendar" onclick="switchDhView('calendar')"
+            class="px-4 py-2 rounded-md text-sm font-medium transition-colors bg-white dark:bg-slate-600 text-gray-900 dark:text-white shadow">
+        Calendar
+    </button>
+    <button id="dh-tab-gantt" onclick="switchDhView('gantt')"
+            class="px-4 py-2 rounded-md text-sm font-medium transition-colors text-gray-600 dark:text-gray-300 hover:text-gray-900 dark:hover:text-white">
+        Gantt by Project
+    </button>
+    <button id="dh-tab-byunit" onclick="switchDhView('byunit')"
+            class="px-4 py-2 rounded-md text-sm font-medium transition-colors text-gray-600 dark:text-gray-300 hover:text-gray-900 dark:hover:text-white">
+        Gantt by Unit
+    </button>
+</div>
+
+<!-- KPI strip -->
+<div class="flex flex-wrap items-center gap-4 mb-6">
+    <div class="flex items-center gap-3 text-sm bg-white dark:bg-slate-800 rounded-lg px-4 py-2 shadow">
+        <span class="text-gray-500 dark:text-gray-400">{{ calendar.projects | length }} project{{ '' if calendar.projects | length == 1 else 's' }}</span>
+        <span class="text-gray-300 dark:text-gray-600">|</span>
+        <span class="text-gray-500 dark:text-gray-400">{{ calendar.total_active_units }} unique units</span>
+        <span class="text-gray-300 dark:text-gray-600">|</span>
+        <span class="text-gray-500 dark:text-gray-400">{{ calendar.total_assignments }} assignment{{ '' if calendar.total_assignments == 1 else 's' }} in window</span>
+    </div>
+    {% if calendar.projects %}
+    <details class="bg-white dark:bg-slate-800 rounded-lg shadow px-4 py-2">
+        <summary class="cursor-pointer text-sm font-medium text-gray-700 dark:text-gray-300 select-none">Project legend</summary>
+        <div class="flex flex-wrap items-center gap-x-4 gap-y-2 mt-3 pt-3 border-t border-gray-200 dark:border-gray-700">
+            {% for p in calendar.projects %}
+            <a href="/projects/{{ p.id }}"
+               class="flex items-center gap-1.5 text-sm text-gray-700 dark:text-gray-300 hover:text-seismo-orange">
+                <span class="w-3 h-1.5 rounded-full flex-shrink-0" style="background-color: {{ p.color }};"></span>
+                {{ p.name }}
+                <span class="text-xs text-gray-400 dark:text-gray-500">·</span>
+                <span class="text-xs text-gray-500 dark:text-gray-400">{{ p.assignment_count }}</span>
+            </a>
+            {% endfor %}
+        </div>
+    </details>
+    {% endif %}
+</div>
+
+<!-- ─── Calendar view ─── -->
+<div id="dh-view-calendar">
+
+<!-- Calendar grid -->
+{% if calendar.projects %}
+<div class="dh-calendar-grid mb-6">
+    {% for month_data in calendar.months %}
+    <div class="dh-month-card">
+        <h3 class="font-semibold text-gray-900 dark:text-white mb-2 text-center">
+            {{ month_data.short_name }} '{{ month_data.year_short }}
+        </h3>
+        <div class="dh-day-grid">
+            <div class="dh-day-header">S</div>
+            <div class="dh-day-header">M</div>
+            <div class="dh-day-header">T</div>
+            <div class="dh-day-header">W</div>
+            <div class="dh-day-header">T</div>
+            <div class="dh-day-header">F</div>
+            <div class="dh-day-header">S</div>
+
+            {# Sunday-first alignment: shift Monday=0 → Sunday=0 #}
+            {% set first_offset = (month_data.first_weekday + 1) % 7 %}
+            {% for i in range(first_offset) %}
+                <div class="dh-day-cell empty"></div>
+            {% endfor %}
+
+            {% for day_num in range(1, month_data.num_days + 1) %}
+                {% set date_str = '%04d-%02d-%02d' | format(month_data.year, month_data.month, day_num) %}
+                {% set is_today = date_str == today %}
+                {% set day_proj_ids = month_data.active_days.get(day_num, []) %}
+                <div class="dh-day-cell{% if is_today %} today ring-2 ring-seismo-orange{% endif %}"
+                     onclick="openDhDay('{{ date_str }}')"
+                     title="{{ date_str }} — {{ day_proj_ids | length }} project{{ '' if day_proj_ids | length == 1 else 's' }}">
+                    <span class="dh-day-num">{{ day_num }}</span>
+                    {% if day_proj_ids %}
+                    <span class="dh-bars">
+                        {% for pid in day_proj_ids[:4] %}
+                            {% set p = (calendar.projects | selectattr('id', 'equalto', pid) | first) %}
+                            {% if p %}
+                            <span class="dh-bar" style="background-color: {{ p.color }};"
+                                  title="{{ p.name }}"></span>
+                            {% endif %}
+                        {% endfor %}
+                        {% if day_proj_ids | length > 4 %}
+                            <span class="text-[8px] text-gray-500 leading-none">+{{ day_proj_ids | length - 4 }}</span>
+                        {% endif %}
+                    </span>
+                    {% endif %}
+                </div>
+            {% endfor %}
+        </div>
+    </div>
+    {% endfor %}
+</div>
+
+<!-- Month navigation -->
+<div class="flex items-center justify-center gap-3 mb-8">
+    <a href="/tools/deployment-history?year={{ prev_year }}&month={{ prev_month }}"
+       class="px-3 py-2 rounded-lg bg-gray-100 dark:bg-gray-700 hover:bg-gray-200 dark:hover:bg-gray-600 text-gray-700 dark:text-gray-300"
+       title="Previous month">
+        <svg class="w-5 h-5" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+            <path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M15 19l-7-7 7-7"/>
+        </svg>
+    </a>
+    <span class="text-lg font-bold text-gray-900 dark:text-white px-3">
+        {{ calendar.months[0].short_name }} '{{ calendar.months[0].year_short }} – {{ calendar.months[11].short_name }} '{{ calendar.months[11].year_short }}
+    </span>
+    <a href="/tools/deployment-history?year={{ next_year }}&month={{ next_month }}"
+       class="px-3 py-2 rounded-lg bg-gray-100 dark:bg-gray-700 hover:bg-gray-200 dark:hover:bg-gray-600 text-gray-700 dark:text-gray-300"
+       title="Next month">
+        <svg class="w-5 h-5" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+            <path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M9 5l7 7-7 7"/>
+        </svg>
+    </a>
+    <a href="/tools/deployment-history"
+       class="ml-2 px-4 py-2 rounded-lg bg-seismo-orange text-white hover:bg-orange-600">
+        Recent
+    </a>
+</div>
+
+{% else %}
+<div class="bg-white dark:bg-slate-800 rounded-xl shadow-lg p-8 text-center text-gray-500 dark:text-gray-400">
+    <svg class="w-12 h-12 mx-auto mb-3 opacity-40" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+        <path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M8 7V3m8 4V3m-9 8h10M5 21h14a2 2 0 002-2V7a2 2 0 00-2-2H5a2 2 0 00-2 2v12a2 2 0 002 2z"/>
+    </svg>
+    <p class="text-sm">No deployments in this window.</p>
+    <p class="text-xs mt-1">Try the navigation buttons below to look at a different range.</p>
+</div>
+{% endif %}
+
+</div>  {# /#dh-view-calendar #}
+
+<!-- ─── Gantt view ─── -->
+<div id="dh-view-gantt" class="hidden">
+{% if calendar.projects %}
+    <div class="bg-white dark:bg-slate-800 rounded-xl shadow-lg p-4 mb-6 overflow-x-auto">
+        <p class="text-xs text-gray-500 dark:text-gray-400 mb-3">
+            One row per project.  Each bar is one assignment window (unit at a location).
+            Hover for details, click to open the project.
+            Active deployments end at "now" with a small white tip.
+        </p>
+        <svg id="dh-gantt-svg" preserveAspectRatio="none"
+             style="width: 100%; min-width: 800px;"></svg>
+    </div>
+
+    <!-- Same nav as calendar view, repeated here so the Gantt view has its own. -->
+    <div class="flex items-center justify-center gap-3 mb-8">
+        <a href="/tools/deployment-history?year={{ prev_year }}&month={{ prev_month }}#gantt"
+           class="px-3 py-2 rounded-lg bg-gray-100 dark:bg-gray-700 hover:bg-gray-200 dark:hover:bg-gray-600 text-gray-700 dark:text-gray-300"
+           title="Previous month">
+            <svg class="w-5 h-5" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+                <path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M15 19l-7-7 7-7"/>
+            </svg>
+        </a>
+        <span class="text-lg font-bold text-gray-900 dark:text-white px-3">
+            {{ calendar.months[0].short_name }} '{{ calendar.months[0].year_short }} – {{ calendar.months[11].short_name }} '{{ calendar.months[11].year_short }}
+        </span>
+        <a href="/tools/deployment-history?year={{ next_year }}&month={{ next_month }}#gantt"
+           class="px-3 py-2 rounded-lg bg-gray-100 dark:bg-gray-700 hover:bg-gray-200 dark:hover:bg-gray-600 text-gray-700 dark:text-gray-300"
+           title="Next month">
+            <svg class="w-5 h-5" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+                <path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M9 5l7 7-7 7"/>
+            </svg>
+        </a>
+        <a href="/tools/deployment-history#gantt"
+           class="ml-2 px-4 py-2 rounded-lg bg-seismo-orange text-white hover:bg-orange-600">
+            Recent
+        </a>
+    </div>
+{% else %}
+    <div class="bg-white dark:bg-slate-800 rounded-xl shadow-lg p-8 text-center text-gray-500 dark:text-gray-400">
+        <p class="text-sm">No deployments in this window.</p>
+    </div>
+{% endif %}
+</div>  {# /#dh-view-gantt #}
+
+<!-- ─── Gantt-by-Unit view ─── -->
+<div id="dh-view-byunit" class="hidden">
+{% if calendar.units %}
+    <div class="bg-white dark:bg-slate-800 rounded-xl shadow-lg p-4 mb-6 overflow-x-auto">
+        <p class="text-xs text-gray-500 dark:text-gray-400 mb-3">
+            One row per seismograph that had ≥1 assignment in this window.
+            Bars are colored by <strong>project</strong>, so an operator can read where each unit travelled
+            across jobs.  Active deployments end at "now" with a small white tip.
+            Click a unit ID to open its detail page; click a bar to open the bar's project.
+        </p>
+        <svg id="dh-byunit-svg" preserveAspectRatio="none"
+             style="width: 100%; min-width: 800px;"></svg>
+    </div>
+
+    <div class="flex items-center justify-center gap-3 mb-8">
+        <a href="/tools/deployment-history?year={{ prev_year }}&month={{ prev_month }}#byunit"
+           class="px-3 py-2 rounded-lg bg-gray-100 dark:bg-gray-700 hover:bg-gray-200 dark:hover:bg-gray-600 text-gray-700 dark:text-gray-300"
+           title="Previous month">
+            <svg class="w-5 h-5" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+                <path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M15 19l-7-7 7-7"/>
+            </svg>
+        </a>
+        <span class="text-lg font-bold text-gray-900 dark:text-white px-3">
+            {{ calendar.months[0].short_name }} '{{ calendar.months[0].year_short }} – {{ calendar.months[11].short_name }} '{{ calendar.months[11].year_short }}
+        </span>
+        <a href="/tools/deployment-history?year={{ next_year }}&month={{ next_month }}#byunit"
+           class="px-3 py-2 rounded-lg bg-gray-100 dark:bg-gray-700 hover:bg-gray-200 dark:hover:bg-gray-600 text-gray-700 dark:text-gray-300"
+           title="Next month">
+            <svg class="w-5 h-5" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+                <path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M9 5l7 7-7 7"/>
+            </svg>
+        </a>
+        <a href="/tools/deployment-history#byunit"
+           class="ml-2 px-4 py-2 rounded-lg bg-seismo-orange text-white hover:bg-orange-600">
+            Recent
+        </a>
+    </div>
+{% else %}
+    <div class="bg-white dark:bg-slate-800 rounded-xl shadow-lg p-8 text-center text-gray-500 dark:text-gray-400">
+        <p class="text-sm">No unit deployments in this window.</p>
+    </div>
+{% endif %}
+</div>  {# /#dh-view-byunit #}
+
+<!-- Day-detail side panel -->
+<div id="dh-day-panel-backdrop"
+     class="fixed inset-0 bg-black/30 z-40 hidden transition-opacity"
+     onclick="closeDhDayPanel()"></div>
+<div id="dh-day-panel"
+     class="fixed top-0 right-0 h-screen w-full max-w-md bg-white dark:bg-slate-800 shadow-2xl z-50 hidden transform translate-x-full transition-transform duration-300 overflow-y-auto">
+    <div class="sticky top-0 bg-white dark:bg-slate-800 border-b border-gray-200 dark:border-gray-700 px-5 py-4 flex items-center justify-between">
+        <div>
+            <h2 class="text-lg font-semibold text-gray-900 dark:text-white" id="dh-day-panel-title">Deployments on…</h2>
+            <p class="text-xs text-gray-500 dark:text-gray-400" id="dh-day-panel-subtitle"></p>
+        </div>
+        <button onclick="closeDhDayPanel()" class="text-gray-400 hover:text-gray-700 dark:hover:text-gray-200">
+            <svg class="w-5 h-5" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+                <path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M6 18L18 6M6 6l12 12"/>
+            </svg>
+        </button>
+    </div>
+    <div id="dh-day-panel-body" class="p-5 space-y-3">
+        <div class="text-center py-8 text-gray-500 dark:text-gray-400 text-sm">
+            <div class="animate-spin rounded-full h-6 w-6 border-b-2 border-seismo-orange mx-auto mb-2"></div>
+            Loading…
+        </div>
+    </div>
+</div>
+
+<script>
+function _dhEsc(s) {
+    if (s == null) return '';
+    return String(s).replace(/&/g, '&amp;').replace(/</g, '&lt;').replace(/>/g, '&gt;').replace(/"/g, '&quot;');
+}
+
+async function openDhDay(dateStr) {
+    const panel    = document.getElementById('dh-day-panel');
+    const backdrop = document.getElementById('dh-day-panel-backdrop');
+    const title    = document.getElementById('dh-day-panel-title');
+    const sub      = document.getElementById('dh-day-panel-subtitle');
+    const body     = document.getElementById('dh-day-panel-body');
+
+    title.textContent = 'Deployments on ' + dateStr;
+    sub.textContent   = '';
+    body.innerHTML    = `<div class="text-center py-8 text-gray-500 dark:text-gray-400 text-sm">
+        <div class="animate-spin rounded-full h-6 w-6 border-b-2 border-seismo-orange mx-auto mb-2"></div>
+        Loading…
+    </div>`;
+
+    panel.classList.remove('hidden');
+    backdrop.classList.remove('hidden');
+    requestAnimationFrame(() => panel.classList.remove('translate-x-full'));
+
+    try {
+        const r = await fetch(`/api/admin/deployment-history/day?target_date=${encodeURIComponent(dateStr)}`);
+        if (!r.ok) throw new Error('HTTP ' + r.status);
+        const d = await r.json();
+        renderDhDayPanel(d, dateStr);
+    } catch (e) {
+        body.innerHTML = `<p class="text-sm text-red-500">Failed to load: ${_dhEsc(e.message)}</p>`;
+    }
+}
+
+function renderDhDayPanel(d, dateStr) {
+    const sub  = document.getElementById('dh-day-panel-subtitle');
+    const body = document.getElementById('dh-day-panel-body');
+
+    sub.textContent = `${d.count} active deployment${d.count === 1 ? '' : 's'}`;
+
+    if (d.count === 0) {
+        body.innerHTML = '<p class="text-sm text-gray-500 dark:text-gray-400">No active deployments on this date.</p>';
+        return;
+    }
+
+    // Group by project for cleaner display.
+    const byProj = {};
+    for (const dep of d.deployments) {
+        const key = dep.project_id || '_none';
+        if (!byProj[key]) byProj[key] = { name: dep.project_name, color: dep.project_color, items: [] };
+        byProj[key].items.push(dep);
+    }
+
+    let html = '';
+    for (const pid of Object.keys(byProj)) {
+        const proj = byProj[pid];
+        html += `<div class="space-y-1">
+            <div class="flex items-center justify-between">
+                <a href="/projects/${_dhEsc(pid)}" class="flex items-center gap-2 font-medium text-gray-900 dark:text-white hover:text-seismo-orange">
+                    <span class="w-3 h-3 rounded-full" style="background-color: ${proj.color};"></span>
+                    ${_dhEsc(proj.name)}
+                </a>
+                <span class="text-xs text-gray-500 dark:text-gray-400">${proj.items.length} unit${proj.items.length === 1 ? '' : 's'}</span>
+            </div>
+            <div class="space-y-1 ml-5">`;
+        for (const dep of proj.items) {
+            const activeBadge = dep.is_active
+                ? '<span class="text-[10px] uppercase tracking-wider px-1 py-0.5 rounded bg-green-100 text-green-800 dark:bg-green-900/30 dark:text-green-300">active</span>'
+                : '';
+            const sourceTag = dep.source === 'metadata_backfill'
+                ? '<span class="text-[10px] text-blue-600 dark:text-blue-400 italic">auto-backfilled</span>'
+                : '';
+            const windowEnd = dep.is_active ? 'present' : (dep.assigned_until || '').slice(0, 10);
+            const windowStart = (dep.assigned_at || '').slice(0, 10);
+            html += `<div class="flex items-center justify-between gap-2 py-1 text-sm">
+                <div class="min-w-0 flex-1">
+                    <div class="flex items-center gap-2 flex-wrap">
+                        <a href="/unit/${_dhEsc(dep.unit_id)}" class="font-mono font-medium text-seismo-orange hover:text-seismo-navy">${_dhEsc(dep.unit_id)}</a>
+                        ${activeBadge}
+                        ${sourceTag}
+                    </div>
+                    <div class="text-xs text-gray-500 dark:text-gray-400 truncate">
+                        📍 <a href="/projects/${_dhEsc(pid)}/nrl/${_dhEsc(dep.location_id)}" class="hover:text-seismo-orange">${_dhEsc(dep.location_name)}</a>
+                    </div>
+                    <div class="text-[11px] text-gray-400 dark:text-gray-500 font-mono">${windowStart} → ${windowEnd}</div>
+                </div>
+            </div>`;
+        }
+        html += `</div></div>`;
+    }
+    body.innerHTML = html;
+}
+
+function closeDhDayPanel() {
+    const panel    = document.getElementById('dh-day-panel');
+    const backdrop = document.getElementById('dh-day-panel-backdrop');
+    panel.classList.add('translate-x-full');
+    setTimeout(() => {
+        panel.classList.add('hidden');
+        backdrop.classList.add('hidden');
+    }, 300);
+}
+
+document.addEventListener('keydown', (e) => {
+    if (e.key === 'Escape') closeDhDayPanel();
+});
+
+// ── Tab switcher ────────────────────────────────────────────────────
+const _DH_TABS = {
+    calendar: { view: 'dh-view-calendar', btn: 'dh-tab-calendar', hash: '',         render: null },
+    gantt:    { view: 'dh-view-gantt',    btn: 'dh-tab-gantt',    hash: '#gantt',   render: () => renderDhGantt() },
+    byunit:   { view: 'dh-view-byunit',   btn: 'dh-tab-byunit',   hash: '#byunit',  render: () => renderDhByUnit() },
+};
+
+function switchDhView(which) {
+    const target = _DH_TABS[which] || _DH_TABS.calendar;
+    const activeCls = ['bg-white', 'dark:bg-slate-600', 'text-gray-900', 'dark:text-white', 'shadow'];
+    const dormantCls = ['text-gray-600', 'dark:text-gray-300', 'hover:text-gray-900', 'dark:hover:text-white'];
+    // Hide all views, dormant-style all tabs, then activate the chosen one.
+    for (const key of Object.keys(_DH_TABS)) {
+        const t = _DH_TABS[key];
+        const v = document.getElementById(t.view);
+        const b = document.getElementById(t.btn);
+        if (v) v.classList.add('hidden');
+        if (b) { b.classList.remove(...activeCls); b.classList.add(...dormantCls); }
+    }
+    const v = document.getElementById(target.view);
+    const b = document.getElementById(target.btn);
+    if (v) v.classList.remove('hidden');
+    if (b) { b.classList.add(...activeCls); b.classList.remove(...dormantCls); }
+    // URL hash sync.
+    const wanted = target.hash;
+    const cur    = window.location.hash || '';
+    if (cur !== wanted) {
+        history.replaceState(null, '', window.location.pathname + window.location.search + wanted);
+    }
+    if (target.render) target.render();
+}
+
+// Land on the requested view if the URL hash matches.
+const _initialHash = window.location.hash;
+if (_initialHash === '#gantt' || _initialHash === '#byunit') {
+    document.addEventListener('DOMContentLoaded', () => switchDhView(_initialHash.slice(1)));
+}
+
+// ── Gantt renderer ──────────────────────────────────────────────────
+// Server-rendered data: per-project list with each project's bars
+// (assignment windows clipped to the visible window).
+const _dhProjects = {{ calendar.projects | tojson }};
+const _dhWindowStart = {{ calendar.window.first_date | tojson }};
+const _dhWindowEnd   = {{ calendar.window.last_date  | tojson }};
+
+let _ganttRendered = false;
+function renderDhGantt() {
+    if (_ganttRendered) return;   // build once; data doesn't change after page load
+    _ganttRendered = true;
+    const svg = document.getElementById('dh-gantt-svg');
+    if (!svg) return;
+    if (!_dhProjects || _dhProjects.length === 0) {
+        svg.innerHTML = '';
+        return;
+    }
+
+    const isDark = document.documentElement.classList.contains('dark');
+    const labelColor = isDark ? '#9ca3af' : '#6b7280';
+    const gridColor  = isDark ? '#374151' : '#e5e7eb';
+    const rowAltBg   = isDark ? '#1e293b' : '#f9fafb';
+    const todayColor = '#f48b1c';
+
+    // Geometry.  The Gantt SVG has a left "labels" gutter and a right
+    // time-axis area.  Width is fluid (matches container); height grows
+    // with the number of project rows.
+    const containerW = svg.parentElement.clientWidth || 1000;
+    const width      = Math.max(containerW, 800);
+    const labelW     = 220;
+    const padTop     = 36;       // room for month labels above
+    const padBottom  = 16;
+    const rowH       = 36;
+    const barH       = 18;
+    const height     = padTop + padBottom + _dhProjects.length * rowH;
+
+    const usableW = width - labelW - 8;
+
+    const tStart = new Date(_dhWindowStart + 'T00:00:00Z').getTime();
+    const tEnd   = new Date(_dhWindowEnd   + 'T23:59:59Z').getTime();
+    const tRange = tEnd - tStart;
+    const xFor = (d) => {
+        const ms = (typeof d === 'string') ? new Date(d + 'T00:00:00Z').getTime() : d;
+        return labelW + Math.max(0, Math.min(usableW, (ms - tStart) / tRange * usableW));
+    };
+
+    // Month gridlines + month labels along the top.
+    // Walk every 1st-of-month inside the window.
+    const monthsParts = [];
+    const cursor = new Date(_dhWindowStart + 'T00:00:00Z');
+    cursor.setUTCDate(1);
+    while (cursor.getTime() <= tEnd) {
+        const x = xFor(cursor);
+        const label = cursor.toLocaleDateString('en-US', { month: 'short', year: '2-digit', timeZone: 'UTC' });
+        monthsParts.push(`<line x1="${x}" y1="${padTop}" x2="${x}" y2="${height - padBottom}" stroke="${gridColor}" stroke-width="1"/>`);
+        monthsParts.push(`<text x="${x + 2}" y="${padTop - 6}" font-size="10" fill="${labelColor}" font-family="system-ui,sans-serif">${label}</text>`);
+        cursor.setUTCMonth(cursor.getUTCMonth() + 1);
+    }
+
+    // Today marker.
+    const now = Date.now();
+    let todayMarker = '';
+    if (now >= tStart && now <= tEnd) {
+        const x = xFor(now);
+        todayMarker = `<line x1="${x}" y1="${padTop}" x2="${x}" y2="${height - padBottom}" stroke="${todayColor}" stroke-width="2" stroke-dasharray="3 2" opacity="0.85"/>
+            <text x="${x + 3}" y="${padTop - 20}" font-size="9" fill="${todayColor}" font-family="system-ui,sans-serif">today</text>`;
+    }
+
+    // Build rows.
+    const rowParts = [];
+    _dhProjects.forEach((proj, idx) => {
+        const y = padTop + idx * rowH;
+        // Alternating row background.
+        if (idx % 2 === 1) {
+            rowParts.push(`<rect x="0" y="${y}" width="${width}" height="${rowH}" fill="${rowAltBg}"/>`);
+        }
+        // Project label (clipped to gutter, clickable).
+        const labelText = proj.name.length > 28 ? proj.name.slice(0, 26) + '…' : proj.name;
+        rowParts.push(`<a href="/projects/${_dhEsc(proj.id)}" target="_top">
+            <rect x="0" y="${y}" width="${labelW}" height="${rowH}" fill="transparent"/>
+            <circle cx="14" cy="${y + rowH / 2}" r="4" fill="${proj.color}"/>
+            <text x="24" y="${y + rowH / 2 + 4}" font-size="12" fill="${labelColor}"
+                  font-family="system-ui,sans-serif"
+                  title="${_dhEsc(proj.name)}">
+                ${_dhEsc(labelText)}
+            </text>
+        </a>`);
+        // Bars for each assignment in this project.
+        for (const bar of (proj.bars || [])) {
+            const x1 = xFor(bar.start);
+            const x2 = xFor(bar.end);
+            const barW = Math.max(x2 - x1, 2);
+            const by = y + (rowH - barH) / 2;
+            const tip = `${bar.unit_id} @ ${bar.location_name}\n${bar.start} → ${bar.is_active ? 'present' : bar.end}`;
+            rowParts.push(`<g style="cursor: pointer;">
+                <title>${_dhEsc(tip)}</title>
+                <rect x="${x1}" y="${by}" width="${barW}" height="${barH}"
+                      rx="3"
+                      fill="${proj.color}" opacity="${bar.is_active ? 1.0 : 0.75}"
+                      ${bar.source === 'metadata_backfill' ? 'stroke="#3b82f6" stroke-width="1.5"' : ''}/>
+                ${bar.is_active ? `<rect x="${x2 - 3}" y="${by}" width="3" height="${barH}" fill="#ffffff" opacity="0.8"/>` : ''}
+            </g>`);
+        }
+    });
+
+    svg.setAttribute('viewBox', `0 0 ${width} ${height}`);
+    svg.setAttribute('height', height);
+    svg.innerHTML = monthsParts.join('') + rowParts.join('') + todayMarker;
+}
+
+// ── Gantt-by-Unit renderer ──────────────────────────────────────────
+// Inverts the Gantt: rows = seismographs, bars = assignment windows
+// colored by project (so an operator can read where each unit went
+// across jobs).  Shares the time-axis geometry with renderDhGantt().
+const _dhUnits = {{ calendar.units | tojson }};
+let _byunitRendered = false;
+function renderDhByUnit() {
+    if (_byunitRendered) return;
+    _byunitRendered = true;
+    const svg = document.getElementById('dh-byunit-svg');
+    if (!svg) return;
+    if (!_dhUnits || _dhUnits.length === 0) {
+        svg.innerHTML = '';
+        return;
+    }
+
+    const isDark = document.documentElement.classList.contains('dark');
+    const labelColor = isDark ? '#9ca3af' : '#6b7280';
+    const labelStrong = isDark ? '#e5e7eb' : '#111827';
+    const gridColor  = isDark ? '#374151' : '#e5e7eb';
+    const rowAltBg   = isDark ? '#1e293b' : '#f9fafb';
+    const todayColor = '#f48b1c';
+
+    const containerW = svg.parentElement.clientWidth || 1000;
+    const width      = Math.max(containerW, 800);
+    const labelW     = 160;
+    const padTop     = 36;
+    const padBottom  = 16;
+    const rowH       = 32;
+    const barH       = 16;
+    const height     = padTop + padBottom + _dhUnits.length * rowH;
+
+    const usableW = width - labelW - 8;
+    const tStart = new Date(_dhWindowStart + 'T00:00:00Z').getTime();
+    const tEnd   = new Date(_dhWindowEnd   + 'T23:59:59Z').getTime();
+    const tRange = tEnd - tStart;
+    const xFor = (d) => {
+        const ms = (typeof d === 'string') ? new Date(d + 'T00:00:00Z').getTime() : d;
+        return labelW + Math.max(0, Math.min(usableW, (ms - tStart) / tRange * usableW));
+    };
+
+    // Month gridlines + labels (same as renderDhGantt).
+    const monthsParts = [];
+    const cursor = new Date(_dhWindowStart + 'T00:00:00Z');
+    cursor.setUTCDate(1);
+    while (cursor.getTime() <= tEnd) {
+        const x = xFor(cursor);
+        const label = cursor.toLocaleDateString('en-US', { month: 'short', year: '2-digit', timeZone: 'UTC' });
+        monthsParts.push(`<line x1="${x}" y1="${padTop}" x2="${x}" y2="${height - padBottom}" stroke="${gridColor}" stroke-width="1"/>`);
+        monthsParts.push(`<text x="${x + 2}" y="${padTop - 6}" font-size="10" fill="${labelColor}" font-family="system-ui,sans-serif">${label}</text>`);
+        cursor.setUTCMonth(cursor.getUTCMonth() + 1);
+    }
+
+    const now = Date.now();
+    let todayMarker = '';
+    if (now >= tStart && now <= tEnd) {
+        const x = xFor(now);
+        todayMarker = `<line x1="${x}" y1="${padTop}" x2="${x}" y2="${height - padBottom}" stroke="${todayColor}" stroke-width="2" stroke-dasharray="3 2" opacity="0.85"/>
+            <text x="${x + 3}" y="${padTop - 20}" font-size="9" fill="${todayColor}" font-family="system-ui,sans-serif">today</text>`;
+    }
+
+    const rowParts = [];
+    _dhUnits.forEach((unit, idx) => {
+        const y = padTop + idx * rowH;
+        if (idx % 2 === 1) {
+            rowParts.push(`<rect x="0" y="${y}" width="${width}" height="${rowH}" fill="${rowAltBg}"/>`);
+        }
+        // Unit label: opens /unit/{id} when clicked.  Active-now dot.
+        const activeDot = unit.any_active
+            ? `<circle cx="12" cy="${y + rowH / 2}" r="3.5" fill="#22c55e"/>`
+            : `<circle cx="12" cy="${y + rowH / 2}" r="3.5" fill="${labelColor}" opacity="0.4"/>`;
+        rowParts.push(`<a href="/unit/${_dhEsc(unit.id)}" target="_top">
+            <rect x="0" y="${y}" width="${labelW}" height="${rowH}" fill="transparent"/>
+            ${activeDot}
+            <text x="22" y="${y + rowH / 2 + 4}" font-size="12" fill="${labelStrong}"
+                  font-family="system-ui,sans-serif" font-weight="500">
+                ${_dhEsc(unit.id)}
+            </text>
+            <text x="${labelW - 8}" y="${y + rowH / 2 + 4}" font-size="10" fill="${labelColor}"
+                  text-anchor="end" font-family="system-ui,sans-serif">
+                ${unit.assignment_count}
+            </text>
+        </a>`);
+        // Bars — colored by the bar's project (not the row).
+        for (const bar of (unit.bars || [])) {
+            const x1 = xFor(bar.start);
+            const x2 = xFor(bar.end);
+            const barW = Math.max(x2 - x1, 2);
+            const by = y + (rowH - barH) / 2;
+            const tip = `${bar.project_name}\n${bar.location_name}\n${bar.start} → ${bar.is_active ? 'present' : bar.end}`;
+            rowParts.push(`<a href="/projects/${_dhEsc(bar.project_id)}" target="_top">
+                <g style="cursor: pointer;">
+                    <title>${_dhEsc(tip)}</title>
+                    <rect x="${x1}" y="${by}" width="${barW}" height="${barH}"
+                          rx="3"
+                          fill="${bar.project_color}" opacity="${bar.is_active ? 1.0 : 0.75}"
+                          ${bar.source === 'metadata_backfill' ? 'stroke="#3b82f6" stroke-width="1.5"' : ''}/>
+                    ${bar.is_active ? `<rect x="${x2 - 3}" y="${by}" width="3" height="${barH}" fill="#ffffff" opacity="0.8"/>` : ''}
+                </g>
+            </a>`);
+        }
+    });
+
+    svg.setAttribute('viewBox', `0 0 ${width} ${height}`);
+    svg.setAttribute('height', height);
+    svg.innerHTML = monthsParts.join('') + rowParts.join('') + todayMarker;
+}
+</script>
+{% endblock %}

templates/base.html

@@ -210,7 +210,9 @@
         </main>
     </div>
 
-    <!-- Bottom Navigation (Mobile Only) -->
+    <!-- Bottom Navigation (Mobile Only) — primary field-work shortcuts.
+         Settings + Projects + Job Planner are reachable via the
+         hamburger Menu (slot 1) which opens the full sidebar drawer. -->
     <nav class="bottom-nav{% if request.query_params.get('embed') == '1' %} hidden{% endif %}">
         <div class="grid grid-cols-4 h-16">
             <button id="hamburgerBtn" class="bottom-nav-btn" onclick="toggleMenu()" aria-label="Menu">
@@ -231,12 +233,11 @@
                 </svg>
                 <span>Devices</span>
             </button>
-            <button class="bottom-nav-btn" data-href="/settings" onclick="window.location.href='/settings'">
+            <button class="bottom-nav-btn" data-href="/sfm" onclick="window.location.href='/sfm'">
                 <svg fill="none" stroke="currentColor" viewBox="0 0 24 24">
-                    <path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M10.325 4.317c.426-1.756 2.924-1.756 3.35 0a1.724 1.724 0 002.573 1.066c1.543-.94 3.31.826 2.37 2.37a1.724 1.724 0 001.065 2.572c1.756.426 1.756 2.924 0 3.35a1.724 1.724 0 00-1.066 2.573c.94 1.543-.826 3.31-2.37 2.37a1.724 1.724 0 00-2.572 1.065c-.426 1.756-2.924 1.756-3.35 0a1.724 1.724 0 00-2.573-1.066c-1.543.94-3.31-.826-2.37-2.37a1.724 1.724 0 00-1.065-2.572c-1.756-.426-1.756-2.924 0-3.35a1.724 1.724 0 001.066-2.573c-.94-1.543.826-3.31 2.37-2.37.996.608 2.296.07 2.572-1.065z"></path>
-                    <path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M15 12a3 3 0 11-6 0 3 3 0 016 0z"></path>
+                    <path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M13 10V3L4 14h7v7l9-11h-7z"></path>
                 </svg>
-                <span>Settings</span>
+                <span>Events</span>
             </button>
         </div>
     </nav>

templates/partials/projects/location_map.html

@@ -0,0 +1,159 @@
+<!-- Reusable project-location map.
+
+  Renders a Leaflet map with one pin per active monitoring location for
+  the given project.  Fetches data from /api/projects/{p}/locations-json
+  on load.
+
+  Required context variable:
+    project_id   — UUID string
+
+  Optional context variable:
+    map_height   — CSS height (default "320px")
+    location_type — filter the fetched list (default: all types)
+
+  Hover any .location-card on the page with a matching
+  data-location-id → highlights the pin.  Click a pin → scrolls
+  the matching card into view + flashes an orange ring.
+
+  isolation:isolate on the container forces a new stacking context so
+  Leaflet's internal z-indexes (200-800) stay contained inside the
+  card instead of leaking out and rendering over modals (z-50).
+-->
+<div class="bg-white dark:bg-slate-800 rounded-xl shadow-lg p-4">
+    <div class="flex items-center justify-between mb-3">
+        <h3 class="text-lg font-semibold text-gray-900 dark:text-white">Location Map</h3>
+        <span class="text-xs text-gray-400 dark:text-gray-500" id="loc-map-status-{{ project_id }}"></span>
+    </div>
+    <div id="loc-map-{{ project_id }}"
+         class="w-full rounded-lg border border-gray-200 dark:border-gray-700"
+         style="height: {{ map_height | default('320px') }}; background: rgba(0,0,0,0.05); isolation: isolate;">
+    </div>
+    <div id="loc-map-empty-{{ project_id }}" class="hidden text-xs text-gray-500 dark:text-gray-400 mt-2 italic text-center">
+        No location coordinates set.  Edit a location and add a <code class="font-mono">lat,lon</code> pair to see it here.
+    </div>
+    <div id="loc-map-missing-{{ project_id }}" class="hidden text-xs text-gray-500 dark:text-gray-400 mt-2"></div>
+</div>
+
+<script>
+(function () {
+    const projectId    = {{ project_id | tojson }};
+    const locationType = {{ (location_type | default(none)) | tojson }};
+    const mapEl        = document.getElementById('loc-map-' + projectId);
+    const emptyMsg     = document.getElementById('loc-map-empty-' + projectId);
+    const missingMsg   = document.getElementById('loc-map-missing-' + projectId);
+    const statusEl     = document.getElementById('loc-map-status-' + projectId);
+    if (!mapEl) return;
+
+    function parseCoords(s) {
+        if (!s) return null;
+        const parts = String(s).split(',').map(x => parseFloat(x.trim()));
+        if (parts.length !== 2 || parts.some(isNaN)) return null;
+        const [lat, lon] = parts;
+        if (lat < -90 || lat > 90 || lon < -180 || lon > 180) return null;
+        return [lat, lon];
+    }
+
+    async function init() {
+        statusEl.textContent = 'loading…';
+        let locs;
+        try {
+            const qs = locationType ? `?location_type=${encodeURIComponent(locationType)}` : '';
+            const r = await fetch(`/api/projects/${projectId}/locations-json${qs}`);
+            if (!r.ok) throw new Error('HTTP ' + r.status);
+            locs = await r.json();
+        } catch (e) {
+            statusEl.textContent = 'failed';
+            mapEl.innerHTML = `<div class="flex items-center justify-center h-full text-sm text-red-500">Map load failed: ${e.message}</div>`;
+            return;
+        }
+        statusEl.textContent = '';
+
+        const withCoords    = [];
+        const withoutCoords = [];
+        for (const loc of locs) {
+            const xy = parseCoords(loc.coordinates);
+            if (xy) withCoords.push({ ...loc, latlon: xy });
+            else    withoutCoords.push(loc);
+        }
+
+        if (withCoords.length === 0) {
+            mapEl.classList.add('hidden');
+            emptyMsg.classList.remove('hidden');
+            return;
+        }
+
+        const map = L.map(mapEl, { scrollWheelZoom: false });
+        L.tileLayer('https://{s}.tile.openstreetmap.org/{z}/{x}/{y}.png', {
+            attribution: '© OpenStreetMap',
+            maxZoom: 18,
+        }).addTo(map);
+
+        const markersById = {};
+        const bounds = [];
+        withCoords.forEach(loc => {
+            const marker = L.circleMarker(loc.latlon, {
+                radius: 8, fillColor: '#f48b1c', color: '#fff',
+                weight: 2, opacity: 1, fillOpacity: 0.9,
+            }).addTo(map);
+            marker.bindTooltip(loc.name, { direction: 'top', offset: [0, -6] });
+            marker.on('click', () => _lmFlashCard(loc.id));
+            markersById[loc.id] = marker;
+            bounds.push(loc.latlon);
+        });
+
+        if (bounds.length === 1) map.setView(bounds[0], 14);
+        else                     map.fitBounds(bounds, { padding: [20, 20] });
+        setTimeout(() => map.invalidateSize(), 100);
+
+        if (withoutCoords.length > 0) {
+            const names = withoutCoords.map(l => l.name).join(', ');
+            missingMsg.textContent = `${withoutCoords.length} location${withoutCoords.length === 1 ? '' : 's'} not shown (no coordinates): ${names}`;
+            missingMsg.classList.remove('hidden');
+        }
+
+        // Hover any .location-card on the page → highlight matching pin.
+        let hoverPinId = null;
+        document.addEventListener('mouseover', (e) => {
+            const card = e.target.closest('.location-card');
+            if (!card) return;
+            const locId = card.dataset.locationId;
+            if (!markersById[locId] || locId === hoverPinId) return;
+            if (hoverPinId) _unhighlight(hoverPinId);
+            _highlight(locId);
+            hoverPinId = locId;
+        });
+        document.addEventListener('mouseout', (e) => {
+            const card = e.target.closest('.location-card');
+            if (!card) return;
+            const related = e.relatedTarget && e.relatedTarget.closest('.location-card');
+            if (related === card) return;
+            if (hoverPinId) {
+                _unhighlight(hoverPinId);
+                hoverPinId = null;
+            }
+        });
+
+        function _highlight(locId) {
+            const m = markersById[locId]; if (!m) return;
+            m.setStyle({ radius: 12, fillColor: '#dc2626', weight: 3 });
+            m.openTooltip();
+            m.bringToFront();
+        }
+        function _unhighlight(locId) {
+            const m = markersById[locId]; if (!m) return;
+            m.setStyle({ radius: 8, fillColor: '#f48b1c', weight: 2 });
+            m.closeTooltip();
+        }
+    }
+
+    function _lmFlashCard(locId) {
+        const card = document.querySelector(`.location-card[data-location-id="${locId}"]`);
+        if (!card) return;
+        card.scrollIntoView({ behavior: 'smooth', block: 'center' });
+        card.classList.add('ring-2', 'ring-seismo-orange');
+        setTimeout(() => card.classList.remove('ring-2', 'ring-seismo-orange'), 1500);
+    }
+
+    init();
+})();
+</script>

templates/partials/projects/project_dashboard.html

@@ -78,128 +78,19 @@
         </div>
     </div>
 
-    <!-- Location Map — replaces the old Upcoming Actions panel for the
-         overview.  Operators get a quick visual of where their locations
-         sit relative to each other.  Pins clickable → scroll to + flash
-         the matching card.  Locations without coordinates land in a
-         "missing coords" hint below the map.
-         For projects with scheduled monitoring activity, the full
-         Upcoming Actions list is still available on the Schedules tab. -->
-    <div class="bg-white dark:bg-slate-800 rounded-xl shadow-lg p-4">
-        <div class="flex items-center justify-between mb-3">
-            <h3 class="text-lg font-semibold text-gray-900 dark:text-white">Location Map</h3>
+    {# Location map — uses the reusable partial that fetches from
+       /api/projects/{p}/locations-json.  Same render is reused on the
+       deeper Vibration tab so both surfaces stay in sync. #}
+    {% with project_id=project.id %}
+        {% include 'partials/projects/location_map.html' %}
+    {% endwith %}
+</div>
+
 {% if upcoming_actions %}
+<div class="mt-3 text-xs text-right text-gray-500 dark:text-gray-400">
     <a href="javascript:void(0)" onclick="switchTab('schedules')"
-                   class="text-xs text-seismo-orange hover:text-seismo-navy whitespace-nowrap">
+       class="text-seismo-orange hover:text-seismo-navy">
         {{ upcoming_actions | length }} upcoming action{{ '' if upcoming_actions | length == 1 else 's' }} →
     </a>
+</div>
 {% endif %}
-        </div>
-        <!-- `isolation: isolate` forces a new stacking context so Leaflet's
-             internal z-indexes (panes at 200-700, controls at 800) stay
-             contained inside this div instead of leaking into the root
-             stacking context and rendering over modals (which have z-50). -->
-        <div id="project-location-map" class="w-full rounded-lg border border-gray-200 dark:border-gray-700"
-             style="height: 320px; background: rgba(0,0,0,0.05); isolation: isolate;"></div>
-        <div id="project-location-map-empty" class="hidden text-xs text-gray-500 dark:text-gray-400 mt-2 italic text-center">
-            No location coordinates set.  Edit a location and add a <code class="font-mono">lat,lon</code> pair to see it here.
-        </div>
-        <div id="project-location-map-missing" class="hidden text-xs text-gray-500 dark:text-gray-400 mt-2"></div>
-    </div>
-</div>
-
-<script>
-(function () {
-    // Build location data from server-side render.  Skip removed
-    // locations (their pins would clutter the active operations view)
-    // and skip ones without parseable coordinates.
-    const locationsRaw = [
-        {% for loc in locations %}
-        {% if not loc.removed_at %}
-        {
-            id:    {{ loc.id | tojson }},
-            name:  {{ loc.name | tojson }},
-            coords: {{ loc.coordinates | tojson if loc.coordinates else 'null' }},
-        }{% if not loop.last %},{% endif %}
-        {% endif %}
-        {% endfor %}
-    ];
-
-    function parseCoords(s) {
-        if (!s) return null;
-        const parts = String(s).split(',').map(x => parseFloat(x.trim()));
-        if (parts.length !== 2 || parts.some(isNaN)) return null;
-        const [lat, lon] = parts;
-        if (lat < -90 || lat > 90 || lon < -180 || lon > 180) return null;
-        return [lat, lon];
-    }
-
-    const withCoords    = [];
-    const withoutCoords = [];
-    for (const loc of locationsRaw) {
-        const xy = parseCoords(loc.coords);
-        if (xy) withCoords.push({ ...loc, latlon: xy });
-        else    withoutCoords.push(loc);
-    }
-
-    const emptyMsg   = document.getElementById('project-location-map-empty');
-    const missingMsg = document.getElementById('project-location-map-missing');
-    const mapEl      = document.getElementById('project-location-map');
-    if (!mapEl) return;
-
-    if (withCoords.length === 0) {
-        // Hide the map block and show a hint.  Don't init Leaflet at all.
-        mapEl.classList.add('hidden');
-        emptyMsg.classList.remove('hidden');
-        return;
-    }
-
-    // Initialise Leaflet.  `L` is loaded globally by base.html.
-    const map = L.map(mapEl, { scrollWheelZoom: false });
-    L.tileLayer('https://{s}.tile.openstreetmap.org/{z}/{x}/{y}.png', {
-        attribution: '© OpenStreetMap',
-        maxZoom: 18,
-    }).addTo(map);
-
-    const markers = [];
-    const bounds  = [];
-    withCoords.forEach(loc => {
-        const marker = L.circleMarker(loc.latlon, {
-            radius:      8,
-            fillColor:   '#f48b1c',
-            color:       '#fff',
-            weight:      2,
-            opacity:     1,
-            fillOpacity: 0.9,
-        }).addTo(map);
-        marker.bindTooltip(loc.name, { direction: 'top', offset: [0, -6] });
-        marker.on('click', () => _flashLocationCard(loc.id));
-        markers.push(marker);
-        bounds.push(loc.latlon);
-    });
-
-    if (bounds.length === 1) {
-        map.setView(bounds[0], 14);
-    } else {
-        map.fitBounds(bounds, { padding: [20, 20] });
-    }
-    // Without this the map renders into a 0×0 area when the partial
-    // first lands via htmx (container size not yet stable).
-    setTimeout(() => map.invalidateSize(), 100);
-
-    if (withoutCoords.length > 0) {
-        const names = withoutCoords.map(l => l.name).join(', ');
-        missingMsg.textContent = `${withoutCoords.length} location${withoutCoords.length === 1 ? '' : 's'} not shown (no coordinates): ${names}`;
-        missingMsg.classList.remove('hidden');
-    }
-
-    // Briefly highlight the matching card to confirm the click.
-    function _flashLocationCard(locId) {
-        const card = document.querySelector(`.location-card[data-location-id="${locId}"]`);
-        if (!card) return;
-        card.scrollIntoView({ behavior: 'smooth', block: 'center' });
-        card.classList.add('ring-2', 'ring-seismo-orange');
-        setTimeout(() => card.classList.remove('ring-2', 'ring-seismo-orange'), 1500);
-    }
-})();
-</script>

templates/projects/detail.html

@@ -101,7 +101,8 @@
                 </div>
             </div>
 
-            <div class="bg-white dark:bg-slate-800 rounded-xl shadow-lg p-6">
+            <div class="grid grid-cols-1 lg:grid-cols-3 gap-6">
+                <div class="bg-white dark:bg-slate-800 rounded-xl shadow-lg p-6 lg:col-span-2">
                     <div class="flex items-center justify-between mb-6">
                         <h2 class="text-xl font-semibold text-gray-900 dark:text-white">Monitoring Locations</h2>
                         <button onclick="openLocationModal('vibration')"
@@ -119,6 +120,16 @@
                         <div class="text-center py-8 text-gray-500">Loading locations...</div>
                     </div>
                 </div>
+
+                {# Reusable location map — fetches from /locations-json
+                   on its own.  Hovering any of the location cards on the
+                   left highlights the matching pin on this map. #}
+                <div>
+                    {% with project_id=project_id, location_type='vibration', map_height='450px' %}
+                        {% include 'partials/projects/location_map.html' %}
+                    {% endwith %}
+                </div>
+            </div>
         </div>
     </div>
 

templates/tools.html

@@ -68,6 +68,24 @@
         </div>
     </a>
 
+    <!-- Deployment History -->
+    <a href="/tools/deployment-history"
+       class="block bg-white dark:bg-slate-800 rounded-xl shadow-lg p-5 hover:shadow-xl transition-shadow border border-transparent hover:border-seismo-orange">
+        <div class="flex items-start gap-3">
+            <div class="w-10 h-10 rounded-lg bg-indigo-100 dark:bg-indigo-900/30 text-indigo-600 dark:text-indigo-400 flex items-center justify-center shrink-0">
+                <svg class="w-5 h-5" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+                    <path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M8 7V3m8 4V3m-9 8h10M5 21h14a2 2 0 002-2V7a2 2 0 00-2-2H5a2 2 0 00-2 2v12a2 2 0 002 2z"/>
+                </svg>
+            </div>
+            <div class="flex-1 min-w-0">
+                <h3 class="font-semibold text-gray-900 dark:text-white">Deployment History</h3>
+                <p class="text-sm text-gray-600 dark:text-gray-400 mt-1">
+                    12-month calendar of every unit assignment across every project. Visual bars per project per day; click a day for the full active-deployments list.
+                </p>
+            </div>
+        </div>
+    </a>
+
     <!-- Reports (per-project) -->
     <a href="/projects"
        class="block bg-white dark:bg-slate-800 rounded-xl shadow-lg p-5 hover:shadow-xl transition-shadow border border-transparent hover:border-seismo-orange">