refactor: factorisation peek panel — NotePeekPanel réutilisable

Architecture:
- components/note-peek/use-note-peek.ts: hook (fetch + state + events)
- components/note-peek/note-peek-content.tsx: rendu markdown/richtext/KaTeX
- components/note-peek/note-peek-panel.tsx: panel (overlay + inline modes)
- components/note-peek/index.ts: exports
- lib/use-scroll-to-block.ts: utilitaire scroll vers data-id

insights/page.tsx:
- ~95 lignes (state + fetch + KaTeX useEffect + AnimatePresence) → 10 lignes
- peek.open(noteId) remplace handleNoteClick complexe
- <NotePeekPanel mode=overlay /> remplace tout le JSX du panel

NotePeekPanel gère:
- markdown (MarkdownContent) + richtext (DOMPurify + KaTeX lazy)
- RTL (slide gauche pour fa/ar)
- prefers-reduced-motion
- role=dialog + aria-modal (overlay mode)
- loading spinner
- bouton Maximize2 + X
- renderContent prop pour custom (éditeur read-only)

.cursor/hooks/state/continual-learning.json

@@ -1,8 +1,8 @@
 {
   "version": 1,
   "lastRunAtMs": 1783196565768,
-  "turnsSinceLastRun": 3,
+  "turnsSinceLastRun": 5,
   "lastTranscriptMtimeMs": 1783196565691.0437,
-  "lastProcessedGenerationId": "d7e4c90f-1f03-4437-a235-3553b9f9cb09",
+  "lastProcessedGenerationId": "7ac52bd5-5714-460a-9c3b-e4b21907d6d7",
   "trialStartedAtMs": null
 }