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/static/locales/en.json

@@ -332,6 +332,9 @@
   "palette.search": "Search…",
   "section.filter.placeholder": "Filter...",
   "section.filter.reset": "Clear filter",
+  "tags.label": "Tags",
+  "tags.hint": "Assign tags for grouping and filtering cards",
+  "tags.placeholder": "Add tag...",
   "section.expand_all": "Expand all sections",
   "section.collapse_all": "Collapse all sections",
   "streams.title": "Sources",