Rename picture-targets to output-targets across entire codebase

Rename all Python modules, classes, API endpoints, config keys, frontend
fetch URLs, and Home Assistant integration URLs from picture-targets to
output-targets. Store loads both new and legacy JSON keys for backward
compatibility with existing data files.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

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

@@ -8,7 +8,7 @@ from fastapi import APIRouter, Depends, HTTPException, Query, WebSocket, WebSock
 
 from wled_controller.api.auth import AuthRequired
 from wled_controller.api.dependencies import (
-    get_picture_target_store,
+    get_output_target_store,
     get_processor_manager,
     get_value_source_store,
 )
@@ -21,7 +21,7 @@ from wled_controller.api.schemas.value_sources import (
 )
 from wled_controller.storage.value_source import ValueSource
 from wled_controller.storage.value_source_store import ValueSourceStore
-from wled_controller.storage.picture_target_store import PictureTargetStore
+from wled_controller.storage.output_target_store import OutputTargetStore
 from wled_controller.core.processing.processor_manager import ProcessorManager
 from wled_controller.utils import get_logger
 
@@ -157,14 +157,14 @@ async def delete_value_source(
     source_id: str,
     _auth: AuthRequired,
     store: ValueSourceStore = Depends(get_value_source_store),
-    target_store: PictureTargetStore = Depends(get_picture_target_store),
+    target_store: OutputTargetStore = Depends(get_output_target_store),
 ):
     """Delete a value source."""
     try:
         # Check if any targets reference this value source
-        from wled_controller.storage.wled_picture_target import WledPictureTarget
+        from wled_controller.storage.wled_output_target import WledOutputTarget
         for target in target_store.get_all_targets():
-            if isinstance(target, WledPictureTarget):
+            if isinstance(target, WledOutputTarget):
                 if getattr(target, "brightness_value_source_id", "") == source_id:
                     raise ValueError(
                         f"Cannot delete: referenced by target '{target.name}'"