Add auto-start targets feature with dashboard section

- Add auto_start boolean field to PictureTarget model (persisted per-target)
- Wire auto_start through API schemas, routes, and store
- Auto-start targets on server boot in main.py lifespan
- Add star toggle button on target cards (next to delete button)
- Add auto-start section on dashboard between performance and profiles
- Remove auto-start section from profiles tab

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

server/src/wled_controller/storage/picture_target.py

@@ -15,6 +15,7 @@ class PictureTarget:
     created_at: datetime
     updated_at: datetime
     description: Optional[str] = None
+    auto_start: bool = False
 
     def register_with_manager(self, manager) -> None:
         """Register this target with the processor manager. Subclasses override."""
@@ -25,12 +26,15 @@ class PictureTarget:
         pass
 
     def update_fields(self, *, name=None, device_id=None, picture_source_id=None,
-                      settings=None, key_colors_settings=None, description=None) -> None:
+                      settings=None, key_colors_settings=None, description=None,
+                      auto_start=None) -> None:
         """Apply mutable field updates. Base handles common fields; subclasses handle type-specific ones."""
         if name is not None:
             self.name = name
         if description is not None:
             self.description = description
+        if auto_start is not None:
+            self.auto_start = auto_start
 
     @property
     def has_picture_source(self) -> bool:
@@ -44,6 +48,7 @@ class PictureTarget:
             "name": self.name,
             "target_type": self.target_type,
             "description": self.description,
+            "auto_start": self.auto_start,
             "created_at": self.created_at.isoformat(),
             "updated_at": self.updated_at.isoformat(),
         }