Add WebSocket, multi API key, geocoding proxy, beacon map picker, and comprehensive bug fixes

- Multi API Key + permission system (read/write/admin) with SHA-256 hash
- WebSocket real-time push (location, alarm, device_status, attendance, bluetooth)
- Geocoding proxy endpoints for Amap POI search and reverse geocode
- Beacon modal map-based location picker with search and click-to-select
- GCJ-02 ↔ WGS-84 bidirectional coordinate conversion
- Data cleanup scheduler (configurable retention days)
- Fix GPS longitude sign inversion (course_status bit 11: 0=East, 1=West)
- Fix 2G CellID 2→3 bytes across all protocols (0x28, 0x2C, parser.py)
- Fix parser loop guards, alarm_source field length, CommandLog.sent_at
- Fix geocoding IMEI parameterization, require_admin import
- Improve API error messages for 422 validation errors
- Remove beacon floor/area fields (consolidated into name)

via [HAPI](https://hapi.run)

Co-Authored-By: HAPI <noreply@hapi.run>

app/protocol/constants.py

@@ -121,7 +121,7 @@ PROTOCOLS_REQUIRING_RESPONSE: FrozenSet[int] = frozenset({
     PROTO_LBS_ADDRESS_REQ,
     PROTO_ADDRESS_QUERY,
     PROTO_TIME_SYNC,
-    PROTO_LBS_MULTI,
+    # Note: PROTO_LBS_MULTI (0x28) does NOT require response; only 0x2E does
     PROTO_HEARTBEAT_EXT,
     PROTO_TIME_SYNC_2,
     # PROTO_GENERAL_INFO (0x94) does NOT require response per protocol doc