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/output_targets.py

@@ -163,8 +163,8 @@ async def create_target(
     except ValueError as e:
         raise HTTPException(status_code=400, detail=str(e))
     except Exception as e:
-        logger.error(f"Failed to create target: {e}")
-        raise HTTPException(status_code=500, detail=str(e))
+        logger.error("Failed to create target: %s", e, exc_info=True)
+        raise HTTPException(status_code=500, detail="Internal server error")
 
 
 @router.get("/api/v1/output-targets", response_model=OutputTargetListResponse, tags=["Targets"])
@@ -291,14 +291,16 @@ async def update_target(
                 css_changed=data.color_strip_source_id is not None,
                 brightness_vs_changed=(data.brightness_value_source_id is not None or kc_brightness_vs_changed),
             )
-        except ValueError:
+        except ValueError as e:
+            logger.debug("Processor config update skipped for target %s: %s", target_id, e)
             pass
 
         # Device change requires async stop -> swap -> start cycle
         if data.device_id is not None:
             try:
                 await manager.update_target_device(target_id, target.device_id)
-            except ValueError:
+            except ValueError as e:
+                logger.debug("Device update skipped for target %s: %s", target_id, e)
                 pass
 
         fire_entity_event("output_target", "updated", target_id)
@@ -309,8 +311,8 @@ async def update_target(
     except ValueError as e:
         raise HTTPException(status_code=404, detail=str(e))
     except Exception as e:
-        logger.error(f"Failed to update target: {e}")
-        raise HTTPException(status_code=500, detail=str(e))
+        logger.error("Failed to update target: %s", e, exc_info=True)
+        raise HTTPException(status_code=500, detail="Internal server error")
 
 
 @router.delete("/api/v1/output-targets/{target_id}", status_code=204, tags=["Targets"])
@@ -325,13 +327,15 @@ async def delete_target(
         # Stop processing if running
         try:
             await manager.stop_processing(target_id)
-        except ValueError:
+        except ValueError as e:
+            logger.debug("Stop processing skipped for target %s (not running): %s", target_id, e)
             pass
 
         # Remove from manager
         try:
             manager.remove_target(target_id)
-        except (ValueError, RuntimeError):
+        except (ValueError, RuntimeError) as e:
+            logger.debug("Remove target from manager skipped for %s: %s", target_id, e)
             pass
 
         # Delete from store
@@ -343,5 +347,5 @@ async def delete_target(
     except ValueError as e:
         raise HTTPException(status_code=404, detail=str(e))
     except Exception as e:
-        logger.error(f"Failed to delete target: {e}")
-        raise HTTPException(status_code=500, detail=str(e))
+        logger.error("Failed to delete target: %s", e, exc_info=True)
+        raise HTTPException(status_code=500, detail="Internal server error")