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/app/api/notebooks/[id]/route.ts

@@ -91,7 +91,7 @@ export async function PATCH(
     if (color !== undefined) updateData.color = color
     if (order !== undefined) updateData.order = order
     if (trashedAt !== undefined) updateData.trashedAt = trashedAt ? new Date(trashedAt) : null
-    if (parentId !== undefined) updateData.parentId = parentId
+    if (parentId !== undefined) updateData.parent = parentId ? { connect: { id: parentId } } : { disconnect: true }
 
     if (trashedAt !== undefined) {
       const descendantIds = await getDescendantIds(id)