feat: Enhance dashboard with filtering options and sync SLM status

- Added a new filtering system to the dashboard for device types and statuses.
- Implemented asynchronous SLM status synchronization to update the Emitter table.
- Updated the status snapshot endpoint to sync SLM status before generating the snapshot.
- Refactored the dashboard HTML to include filter controls and JavaScript for managing filter state.
- Improved the unit detail page to handle modem associations and cascade updates to paired devices.
- Removed redundant code related to syncing start time for measuring devices.

backend/routers/slm_dashboard.py

@@ -167,23 +167,7 @@ async def get_live_view(request: Request, unit_id: str, db: Session = Depends(ge
                 measurement_state = state_data.get("measurement_state", "Unknown")
                 is_measuring = state_data.get("is_measuring", False)
 
-            # If measuring, sync start time from FTP to database (fixes wrong timestamps)
-            if is_measuring:
-                try:
-                    sync_response = await client.post(
-                        f"{SLMM_BASE_URL}/api/nl43/{unit_id}/sync-start-time",
-                        timeout=10.0
-                    )
-                    if sync_response.status_code == 200:
-                        sync_data = sync_response.json()
-                        logger.info(f"Synced start time for {unit_id}: {sync_data.get('message')}")
-                    else:
-                        logger.warning(f"Failed to sync start time for {unit_id}: {sync_response.status_code}")
-                except Exception as e:
-                    # Don't fail the whole request if sync fails
-                    logger.warning(f"Could not sync start time for {unit_id}: {e}")
-
-            # Get live status (now with corrected start time)
+            # Get live status (measurement_start_time is already stored in SLMM database)
             status_response = await client.get(
                 f"{SLMM_BASE_URL}/api/nl43/{unit_id}/live"
             )