fix: deployment capture coords now reach existing locations

The /deploy classify "Assign to existing location" path dropped the captured
GPS — only "Create new location" applied it — so units assigned to pre-existing
coordless locations left those locations without a pin.

- Classify (promote) now backfills the captured GPS onto an existing location
  that has no coordinates (doesn't clobber operator-set coords).
- Add "Reforward info" button on Assigned deployment cards + endpoint
  POST /pending/{id}/resync-location that re-pushes a capture's GPS onto its
  assigned location (explicit action, overwrites). Fixes already-classified
  locations and guards against this recurring. Logged to unit history.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

backend/routers/pending_deployments.py

@@ -296,6 +296,12 @@ async def promote_pending(
         if not location:
             raise HTTPException(status_code=404, detail=f"Location {location_id!r} not found.")
         project_id = location.project_id
+        # Backfill the captured GPS onto the existing location if it doesn't
+        # have coordinates yet. (Previously the captured coords were dropped on
+        # the assign-to-existing path, so only create-new locations got a pin.)
+        # Don't clobber coordinates an operator already set.
+        if pd.coordinates and not (location.coordinates or "").strip():
+            location.coordinates = pd.coordinates
     else:
         # Create-new path.  Need a project (existing or new).
         project_id = payload.get("project_id")
@@ -456,6 +462,50 @@ async def cancel_pending(
     return {"success": True, "cancelled_at": pd.cancelled_at.isoformat()}
 
 
+@router.post("/pending/{pending_id}/resync-location")
+async def resync_location(pending_id: str, db: Session = Depends(get_db)):
+    """Re-push a promoted capture's GPS onto its assigned location.
+
+    Use when a capture's coordinates didn't land on the location (e.g. it was
+    assigned to a pre-existing location that had none). Unlike the auto-backfill
+    on classify, this is an explicit operator action and OVERWRITES the
+    location's coordinates with the captured GPS.
+    """
+    pd = db.query(PendingDeployment).filter_by(id=pending_id).first()
+    if not pd:
+        raise HTTPException(status_code=404, detail="Pending deployment not found.")
+    if pd.status != "assigned" or not pd.resulting_assignment_id:
+        raise HTTPException(status_code=400, detail="Only a promoted (assigned) capture can be re-forwarded.")
+    if not (pd.coordinates or "").strip():
+        raise HTTPException(status_code=400, detail="This capture has no GPS coordinates to forward.")
+
+    asg = db.query(UnitAssignment).filter_by(id=pd.resulting_assignment_id).first()
+    if not asg:
+        raise HTTPException(status_code=404, detail="Resulting assignment not found.")
+    location = db.query(MonitoringLocation).filter_by(id=asg.location_id).first()
+    if not location:
+        raise HTTPException(status_code=404, detail="Assigned location not found.")
+
+    old = location.coordinates
+    location.coordinates = pd.coordinates.strip()
+
+    _record_history(
+        db, unit_id=pd.unit_id,
+        change_type="deployment_coords_reforwarded",
+        old_value=old,
+        new_value=location.coordinates,
+        notes=f"Re-forwarded capture GPS to location '{location.name}'",
+    )
+
+    db.commit()
+    return {
+        "success": True,
+        "location_id": location.id,
+        "location_name": location.name,
+        "coordinates": location.coordinates,
+    }
+
+
 # ── Helpers ───────────────────────────────────────────────────────────────────
 
 def _to_dict(pd: PendingDeployment, unit: Optional[RosterUnit] = None, detail: bool = False) -> dict:

templates/admin/pending_deployments.html

@@ -207,9 +207,19 @@ function _renderPdCard(pd) {
             </button>
         </div>`;
     } else if (pd.status === 'assigned') {
+        const reforward = pd.coordinates
+            ? `<button onclick="reforwardInfo('${_esc(pd.id)}')"
+                    class="mt-2 inline-flex items-center gap-1.5 px-3 py-1.5 text-xs rounded-lg border border-seismo-orange/40 bg-seismo-orange/10 text-seismo-orange hover:bg-seismo-orange/20 transition-colors"
+                    title="Re-push this capture's GPS coordinates onto its assigned location">
+                    <svg class="w-3.5 h-3.5" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+                        <path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M4 4v5h.582m15.356 2A8.001 8.001 0 004.582 9m0 0H9m11 11v-5h-.581m0 0a8.003 8.003 0 01-15.357-2m15.357 2H15"></path>
+                    </svg>
+                    Reforward info
+                </button>`
+            : '';
         footerActions = `<div class="mt-3 text-xs text-green-700 dark:text-green-400">
             Promoted ${_fmtDateTime(pd.promoted_at)} → assignment <span class="font-mono">${_esc((pd.resulting_assignment_id || '').slice(0, 8))}…</span>
-        </div>`;
+        </div>${reforward}`;
     } else if (pd.status === 'cancelled') {
         footerActions = `<div class="mt-3 text-xs text-gray-500 dark:text-gray-400">
             Cancelled ${_fmtDateTime(pd.cancelled_at)}${pd.cancelled_reason ? ` — ${_esc(pd.cancelled_reason)}` : ''}
@@ -459,6 +469,22 @@ async function cancelPending(pendingId) {
     }
 }
 
+// Re-push a promoted capture's GPS coordinates onto its assigned location.
+async function reforwardInfo(pendingId) {
+    try {
+        const r = await fetch(`/api/deployments/pending/${pendingId}/resync-location`, {
+            method: 'POST',
+        });
+        const j = await r.json().catch(() => ({}));
+        if (!r.ok) throw new Error(j.detail || 'HTTP ' + r.status);
+        const msg = `Coordinates synced to "${j.location_name}": ${j.coordinates}`;
+        if (window.showToast) showToast(msg, 'success'); else alert(msg);
+    } catch (e) {
+        const msg = 'Reforward failed: ' + e.message;
+        if (window.showToast) showToast(msg, 'error'); else alert(msg);
+    }
+}
+
 // Kick off the initial load.
 loadPdList();
 // Refresh awaiting count every 30s for the badge.