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/notes-editorial-view.tsx

@@ -141,9 +141,9 @@ export function EditorialNoteMenu({
     startTransition(async () => {
       try {
         await updateNote(note.id, { reminder }, { skipRevalidation: true })
-        const patch = { reminder: reminder?.toISOString() ?? null }
+        const patch = { reminder: (reminder?.toISOString() ?? null) as any }
         onNotePatch?.(note.id, patch)
-        emitNoteChange({ type: 'updated', note: { ...note, reminder: patch.reminder } })
+        emitNoteChange({ type: 'updated', note: { ...note, reminder: patch.reminder } as any })
         setShowReminder(false)
       } catch {
         toast.error(t('general.error'))