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/api/routes/scene_presets.py

@@ -1,7 +1,7 @@
 """Scene preset API routes — CRUD, capture, activate, recapture."""
 
 import uuid
-from datetime import datetime
+from datetime import datetime, timezone
 
 from fastapi import APIRouter, Depends, HTTPException
 
@@ -45,6 +45,7 @@ def _preset_to_response(preset: ScenePreset) -> ScenePresetResponse:
             "fps": t.fps,
         } for t in preset.targets],
         order=preset.order,
+        tags=getattr(preset, 'tags', []),
         created_at=preset.created_at,
         updated_at=preset.updated_at,
     )
@@ -69,13 +70,14 @@ async def create_scene_preset(
     target_ids = set(data.target_ids) if data.target_ids is not None else None
     targets = capture_current_snapshot(target_store, manager, target_ids)
 
-    now = datetime.utcnow()
+    now = datetime.now(timezone.utc)
     preset = ScenePreset(
         id=f"scene_{uuid.uuid4().hex[:8]}",
         name=data.name,
         description=data.description,
         targets=targets,
         order=store.count(),
+        tags=data.tags if data.tags is not None else [],
         created_at=now,
         updated_at=now,
     )
@@ -169,6 +171,7 @@ async def update_scene_preset(
             description=data.description,
             order=data.order,
             targets=new_targets,
+            tags=data.tags,
         )
     except ValueError as e:
         raise HTTPException(status_code=404 if "not found" in str(e).lower() else 400, detail=str(e))