Add tags to all entity types with chip-based input and autocomplete

- Add `tags: List[str]` field to all 13 entity types (devices, output targets,
  CSS sources, picture sources, audio sources, value sources, sync clocks,
  automations, scene presets, capture/audio/PP/pattern templates)
- Update all stores, schemas, and route handlers for tag CRUD
- Add GET /api/v1/tags endpoint aggregating unique tags across all stores
- Create TagInput component with chip display, autocomplete dropdown,
  keyboard navigation, and API-backed suggestions
- Display tag chips on all entity cards (searchable via existing text filter)
- Add tag input to all 14 editor modals with dirty check support
- Add CSS styles and i18n keys (en/ru/zh) for tag UI
- Also includes code review fixes: thread safety, perf, store dedup

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

server/src/wled_controller/storage/wled_output_target.py

@@ -1,8 +1,8 @@
 """LED output target — sends color strip sources to an LED device."""
 
 from dataclasses import dataclass
-from datetime import datetime
-from typing import Optional
+from datetime import datetime, timezone
+from typing import List, Optional
 
 from wled_controller.storage.output_target import OutputTarget
 
@@ -63,9 +63,10 @@ class WledOutputTarget(OutputTarget):
                       brightness_value_source_id=None,
                       fps=None, keepalive_interval=None, state_check_interval=None,
                       min_brightness_threshold=None, adaptive_fps=None, protocol=None,
-                      description=None, **_kwargs) -> None:
+                      description=None, tags: Optional[List[str]] = None,
+                      **_kwargs) -> None:
         """Apply mutable field updates for WLED targets."""
-        super().update_fields(name=name, description=description)
+        super().update_fields(name=name, description=description, tags=tags)
         if device_id is not None:
             self.device_id = device_id
         if color_strip_source_id is not None:
@@ -120,6 +121,7 @@ class WledOutputTarget(OutputTarget):
             adaptive_fps=data.get("adaptive_fps", False),
             protocol=data.get("protocol", "ddp"),
             description=data.get("description"),
-            created_at=datetime.fromisoformat(data.get("created_at", datetime.utcnow().isoformat())),
-            updated_at=datetime.fromisoformat(data.get("updated_at", datetime.utcnow().isoformat())),
+            tags=data.get("tags", []),
+            created_at=datetime.fromisoformat(data.get("created_at", datetime.now(timezone.utc).isoformat())),
+            updated_at=datetime.fromisoformat(data.get("updated_at", datetime.now(timezone.utc).isoformat())),
         )