docs+chore: v0.12.1 — Unit Swap wizard, editable timeline, roster/tz fixes

CHANGELOG entry for the five commits that landed after the v0.12.0 tag:
two features (Unit Swap wizard at /tools/unit-swap, editable deployment
timeline on /unit/{id}) and two correctness fixes (RosterUnit.deployed
now flips on swap/unassign/promote; deployment timeline now respects
user timezone for both display and edits).  No schema migrations.

README bumped to v0.12.1 with new bullets for the post-v0.12.0 features
and several already-shipped items that were missing from the list (SFM
Event DB Manager, Deployment-History calendar + Gantt tabs, reusable
location-map partial).  backend/main.py VERSION constant bumped too.

README.md

@@ -1,4 +1,4 @@
-# Terra-View v0.12.0
+# Terra-View v0.12.1
 Backend API and HTMX-powered web interface for managing a mixed fleet of seismographs and field modems. Track deployments, monitor health in real time, merge roster intent with incoming telemetry, and control your fleet through a unified database and dashboard.
 
 ## Features
@@ -9,15 +9,20 @@ Backend API and HTMX-powered web interface for managing a mixed fleet of seismog
   - **Touch Optimized**: 44x44px minimum touch targets, hamburger menu, bottom navigation bar
   - **Mobile Card View**: Compact unit cards with status dots, tap-to-navigate locations, and detail modals
   - **Background Sync**: Queue edits while offline and automatically sync when connection returns
+- **Field-Deployment Workflow**: One-photo mobile capture at `/deploy` → desk-side classification at `/tools/pending-deployments` → automatic UnitAssignment creation with EXIF GPS
+- **Unit Swap Wizard** (`/tools/unit-swap`): mobile-first 4-step flow for swapping a vibration unit (and optionally its modem) at a monitoring location.  Surfaces benched-fleet candidates as eligible incoming units; cleans up stale modem back-references on swap
+- **Editable Deployment Timeline** on every unit detail page: inline edit / delete each assignment, plus an "Add deployment record" button for backfilling historical windows.  Frees-up previously-orphaned events when their timestamp now falls inside an assignment
 - **Web Dashboard**: Modern, responsive UI with dark/light mode, live HTMX updates, and integrated fleet map
 - **Fleet Monitoring**: Track deployed, benched, retired, and ignored units in separate buckets with unknown-emitter triage
 - **Roster Management**: Full CRUD + CSV import/export, device-type aware metadata, and inline actions from the roster tables
 - **Settings & Safeguards**: `/settings` page exposes roster stats, exports, replace-all imports, and danger-zone reset tools
 - **Device & Modem Metadata**: Capture calibration windows, modem pairings, phone/IP details, and addresses per unit
 - **Status Management**: Automatically mark deployed units as OK, Pending (>12h), or Missing (>24h) based on recent telemetry
-- **Data Ingestion**: Accept reports from emitter scripts via REST API
+- **SFM Event DB Manager** (`/admin/events`): cross-unit event browser with bulk false-trigger flagging and admin-only hard-delete (cleans on-disk binaries + sidecars too) for purging bogus events from misbehaving units
+- **Deployment-History Calendar + Gantt** (`/tools/deployment-history`): fleet-wide 12-month calendar with side-panel day drill-down, plus "Gantt by Project" / "Gantt by Unit" tabs
 - **Photo Management**: Upload and view photos for each unit
-- **Interactive Maps**: Leaflet-based maps showing unit locations with tap-to-navigate for mobile
+- **Interactive Maps**: Leaflet-based maps showing unit locations with tap-to-navigate for mobile (reusable location-map partial across project overview + Vibration tab)
+- **Timezone-Aware Timeline**: deployment assignments display and edit in the user's configured local timezone; UTC stays canonical on disk
 - **SQLite Storage**: Lightweight, file-based database for easy deployment
 - **Database Management**: Comprehensive backup and restore system
   - **Manual Snapshots**: Create on-demand backups with descriptions