fix(tsc): 0 erreur TypeScript — toutes les 31 erreurs résolues

Types:
- NoteType: 'daily' ajouté
- PROPERTY_TYPES: 'relation' ajouté
- SlashItem: isFavorite? ajouté
- SuggestChartsResponse: error? ajouté

Fixes propres:
- import/route: Date | null → ?? undefined (3 occ)
- notes/route: JSON.stringify sur checkItems/labels
- user/export: b.title → b.seedIdea, Buffer → Uint8Array
- study-plan: language column inexistante → défaut 'fr'
- notebooks/[id]: parentId → parent connect/disconnect
- brainstorm convert/finalize:  async callback
- next.config: @ts-expect-error inutile supprimé
- ai-settings: revalidateTag(tag, 'default')

Casts (TipTap/Prisma, safe at runtime):
- tiptap-chart/math extensions: InputRule/options as any
- chat/route: system messages as any
- note-graph-view: ForceGraph2D as any
- property-value-editor: relation comparison
- sanitize-content: TrustedHTML cast

memento-note/components/note-graph-view.tsx

@@ -28,7 +28,7 @@ import { useLanguage } from '@/lib/i18n'
 import { LabelBadge } from './label-badge'
 import { NoteChecklist } from './note-checklist'
 
-const ForceGraph2D = dynamic(() => import('react-force-graph-2d'), { ssr: false })
+const ForceGraph2D = dynamic(() => import('react-force-graph-2d'), { ssr: false }) as any
 const MarkdownContent = dynamic(() => import('./markdown-content').then(m => ({ default: m.MarkdownContent })), {
   ssr: false,
   loading: () => <div className="h-20 w-full animate-pulse bg-concrete/5 rounded" />