refactor: split NoteEditor into focused components + consolidate contexts

Phase 1: NoteEditor Split (64KB → 9 focused components)
- components/note-editor/: types.ts, context, toolbar, title-block,
  content-area, metadata-section, full-page, dialog compositions
- Maintains backwards compatibility via re-export from note-editor.tsx

Phase 2: Context Consolidation (5 → 3 contexts)
- NotebooksContext absorbs LabelContext (labels CRUD)
- EditorUIContext merges HomeViewContext + NotebookDragContext
- Removed: LabelContext, home-view-context, notebook-drag-context

Phase 3: React Query Infrastructure
- Added QueryProvider with @tanstack/react-query
- lib/query-keys.ts: centralized query key definitions
- lib/query-hooks.ts: useNotes, useNotebooksQuery, useLabelsQuery
- lib/use-refresh.ts: hybrid invalidateQueries + triggerRefresh helper
- NotebooksContext: invalidateQueries on mutations (with triggerRefresh fallback)

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

memento-note/components/note-inline-editor.tsx

@@ -52,9 +52,8 @@ import { useAutoTagging } from '@/hooks/use-auto-tagging'
 import { GhostTags } from '@/components/ghost-tags'
 import { useTitleSuggestions } from '@/hooks/use-title-suggestions'
 import { TitleSuggestions } from '@/components/title-suggestions'
-import { useLabels } from '@/context/LabelContext'
-import { useNoteRefresh } from '@/context/NoteRefreshContext'
 import { useNotebooks } from '@/context/notebooks-context'
+import { useNoteRefresh } from '@/context/NoteRefreshContext'
 import { ContextualAIChat } from '@/components/contextual-ai-chat'
 import { formatDistanceToNow } from 'date-fns'
 import { fr } from 'date-fns/locale/fr'
@@ -120,7 +119,7 @@ export function NoteInlineEditor({
       })
     }
   }, [session?.user?.id])
-  const { labels: globalLabels, addLabel } = useLabels()
+  const { labels: globalLabels, addLabel } = useNotebooks()
   const [, startTransition] = useTransition()
   const { triggerRefresh } = useNoteRefresh()