feat(dashboard): clarify the fleet status card and swap map locations to project monitoring location coords.

feat: Location no longer assigned directly to unit, locations and coords are assigned to location only, unit only is deployed or benched.

backend/services/snapshot.py

@@ -10,6 +10,7 @@ from sqlalchemy.orm import Session
 
 from backend.database import get_db_session
 from backend.models import Emitter, RosterUnit, IgnoredUnit
+from backend.services.unit_location import bulk_active_locations
 
 log = logging.getLogger(__name__)
 
@@ -137,6 +138,10 @@ def emit_status_snapshot():
         emitters = {e.id: e for e in db.query(Emitter).all()}
         ignored = {i.id for i in db.query(IgnoredUnit).all()}
 
+        # Active-assignment location lookup for all roster units (direct only;
+        # modems inherit from their paired device below in the derive loop).
+        active_locs = bulk_active_locations(db, list(roster.values()))
+
         # SFM event-forwards are now the primary "last seen" signal for
         # seismographs.  Watcher heartbeats stay as a backup — if SFM is down
         # or hasn't seen a serial, we fall back to Emitter.last_seen.
@@ -225,10 +230,13 @@ def emit_status_snapshot():
                 "ip_address": r.ip_address,
                 "phone_number": r.phone_number,
                     "hardware_model": r.hardware_model,
-                    # Location for mapping
-                    "location": r.location or "",
-                    "address": r.address or "",
-                    "coordinates": r.coordinates or "",
+                    # Location for mapping — sourced from active UnitAssignment
+                    # → MonitoringLocation.  Empty for benched / unassigned.
+                    "address":       (active_locs.get(unit_id) or {}).get("address") or "",
+                    "coordinates":   (active_locs.get(unit_id) or {}).get("coordinates") or "",
+                    "location_name": (active_locs.get(unit_id) or {}).get("name") or "",
+                    "project_id":    (active_locs.get(unit_id) or {}).get("project_id") or "",
+                    "location_id":   (active_locs.get(unit_id) or {}).get("location_id") or "",
                 }
 
         # --- Add unexpected emitter-only units ---
@@ -267,10 +275,12 @@ def emit_status_snapshot():
                     "ip_address": None,
                     "phone_number": None,
                     "hardware_model": None,
-                    # Location fields
-                    "location": "",
+                    # Location fields — unknown units have no assignment
                     "address": "",
                     "coordinates": "",
+                    "location_name": "",
+                    "project_id": "",
+                    "location_id": "",
                 }
 
         # --- Derive modem status from paired devices ---
@@ -301,6 +311,11 @@ def emit_status_snapshot():
                         unit_data["last"] = paired_unit.get("last")
                         unit_data["last_seen_source"] = paired_unit.get("last_seen_source", "none")
                         unit_data["derived_from"] = paired_unit_id
+                        # Inherit deployment location too — modems don't carry
+                        # their own UnitAssignment.
+                        for k in ("address", "coordinates", "location_name", "project_id", "location_id"):
+                            if not unit_data.get(k):
+                                unit_data[k] = paired_unit.get(k, "")
 
         # Separate buckets for UI
         active_units = {