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/user/export/route.ts

@@ -161,7 +161,7 @@ export async function GET() {
       })),
       brainstorms: brainstorms.map((b) => ({
         id: b.id,
-        title: b.title,
+        title: b.seedIdea,
         createdAt: b.createdAt,
         ideasCount: b.ideas.length,
       })),
@@ -196,9 +196,9 @@ export async function GET() {
 
     const canvasFolder = zip.folder('canvases')!
     for (const brainstorm of brainstorms) {
-      const fileBase = uniqueBaseName(brainstorm.title || 'Untitled Brainstorm', brainstorm.id)
+      const fileBase = uniqueBaseName(brainstorm.seedIdea || 'Untitled Brainstorm', brainstorm.id)
 
-      let canvasMd = `# Brainstorm Canvas: ${brainstorm.title || 'Untitled'}\n\n`
+      let canvasMd = `# Brainstorm Canvas: ${brainstorm.seedIdea || 'Untitled'}\n\n`
       canvasMd += `- **Created At:** ${brainstorm.createdAt.toISOString()}\n`
       canvasMd += `- **Updated At:** ${brainstorm.updatedAt.toISOString()}\n`
       canvasMd += `- **Ideas Count:** ${brainstorm.ideas.length}\n\n`
@@ -232,7 +232,7 @@ export async function GET() {
     }))
 
     const offlineCanvases = brainstorms.map((b) => ({
-      title: b.title || 'Untitled Brainstorm',
+      title: b.seedIdea || 'Untitled Brainstorm',
       createdAt: b.createdAt.toISOString(),
       ideas: b.ideas.map((i) => ({
         title: i.title,
@@ -499,7 +499,7 @@ export async function GET() {
     const zipBuffer = await zip.generateAsync({ type: 'nodebuffer' })
 
     const dateString = new Date().toISOString().split('T')[0]
-    return new NextResponse(zipBuffer, {
+    return new NextResponse(new Uint8Array(zipBuffer) as BodyInit, {
       headers: {
         'Content-Type': 'application/zip',
         'Content-Disposition': `attachment; filename="memento-workspace-export-${dateString}.zip"`,