feat: asset-based image/video sources, notification sounds, UI improvements

- Replace URL-based image_source/url fields with image_asset_id/video_asset_id
  on StaticImagePictureSource and VideoCaptureSource (clean break, no migration)
- Resolve asset IDs to file paths at runtime via AssetStore.get_file_path()
- Add EntitySelect asset pickers for image/video in stream editor modal
- Add notification sound configuration (global sound + per-app overrides)
- Unify per-app color and sound overrides into single "Per-App Overrides" section
- Persist notification history between server restarts
- Add asset management system (upload, edit, delete, soft-delete)
- Replace emoji buttons with SVG icons throughout UI
- Various backend improvements: SQLite stores, auth, backup, MQTT, webhooks

server/src/wled_controller/api/routes/system_settings.py

@@ -191,8 +191,10 @@ async def logs_ws(
                 except Exception:
                     break
     except WebSocketDisconnect:
+        logger.debug("Log stream WebSocket disconnected")
         pass
-    except Exception:
+    except Exception as e:
+        logger.debug("Log stream WebSocket error: %s", e)
         pass
     finally:
         log_broadcaster.unsubscribe(queue)
@@ -287,6 +289,7 @@ async def adb_disconnect(_: AuthRequired, request: AdbConnectRequest):
     address = request.address.strip()
     if not address:
         raise HTTPException(status_code=400, detail="Address is required")
+    _validate_adb_address(address)
 
     adb = _get_adb_path()
     logger.info(f"Disconnecting ADB device: {address}")