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/app/actions/notes.ts

@@ -37,6 +37,7 @@ const NOTE_LIST_SELECT = {
   checkItems: true,
   labels: true,
   images: true,
+  illustrationSvg: true,
   links: true,
   reminder: true,
   isReminderDone: true,
@@ -789,6 +790,7 @@ export async function updateNote(id: string, data: {
   checkItems?: CheckItem[] | null
   labels?: string[] | null
   images?: string[] | null
+  illustrationSvg?: string | null
   links?: any[] | null
   reminder?: Date | null
   isMarkdown?: boolean
@@ -844,6 +846,7 @@ export async function updateNote(id: string, data: {
     // labels handled by syncNoteLabels below
     delete updateData.labels
     if ('images' in data) updateData.images = data.images ? JSON.stringify(data.images) : null
+    if ('illustrationSvg' in data) updateData.illustrationSvg = data.illustrationSvg
     if ('links' in data) updateData.links = data.links ? JSON.stringify(data.links) : null
     if ('notebookId' in data) updateData.notebookId = data.notebookId
     // Explicitly handle size to ensure it propagates
@@ -852,7 +855,7 @@ export async function updateNote(id: string, data: {
     // Only update contentUpdatedAt for actual content changes, NOT for property changes
     // (size, color, isPinned, isArchived are properties, not content)
     // skipContentTimestamp=true is used by the inline editor to avoid bumping "Récent" on every auto-save
-    const contentFields = ['title', 'content', 'checkItems', 'images', 'links']
+    const contentFields = ['title', 'content', 'checkItems', 'images', 'links', 'illustrationSvg']
     const isContentChange = contentFields.some(field => field in data)
     if (isContentChange && !options?.skipContentTimestamp) {
       updateData.contentUpdatedAt = new Date()