feat(notes): liens internes, onglet Réseau, living blocks et consentement IA

Rend les liens entre notes visibles et persistants (sync NoteLink au save, auto-save, graphe réseau rafraîchi), ajoute living blocks, Memory Echo, recherche globale, consentement IA explicite et consolide les prototypes design en architectural-grid.

Co-authored-by: Cursor <cursoragent@cursor.com>

memento-note/app/api/blocks/[blockId]/status/route.ts

@@ -0,0 +1,52 @@
+import { NextRequest, NextResponse } from 'next/server'
+import prisma from '@/lib/prisma'
+import { auth } from '@/auth'
+
+function extractBlockContent(html: string, blockId: string): string | null {
+  const regex = new RegExp(
+    `<(?:p|h[1-6]|blockquote)[^>]*data-id="${blockId}"[^>]*>([\\s\\S]*?)<\\/(?:p|h[1-6]|blockquote)>`,
+    'i'
+  )
+  const match = regex.exec(html)
+  if (!match) return null
+  return match[1].replace(/<[^>]+>/g, '').trim()
+}
+
+// GET /api/blocks/[blockId]/status?sourceNoteId=xxx
+export async function GET(
+  request: NextRequest,
+  { params }: { params: Promise<{ blockId: string }> }
+) {
+  const session = await auth()
+  if (!session?.user?.id) {
+    return NextResponse.json({ error: 'Unauthorized' }, { status: 401 })
+  }
+
+  const { blockId } = await params
+  const sourceNoteId = request.nextUrl.searchParams.get('sourceNoteId')
+
+  if (!sourceNoteId) {
+    return NextResponse.json({ error: 'sourceNoteId required' }, { status: 400 })
+  }
+
+  const note = await prisma.note.findFirst({
+    where: { id: sourceNoteId, userId: session.user.id },
+    select: { id: true, title: true, content: true },
+  })
+
+  if (!note) {
+    return NextResponse.json({ exists: false, content: '', sourceNoteTitle: '' })
+  }
+
+  const content = extractBlockContent(note.content, blockId)
+
+  if (content === null) {
+    return NextResponse.json({ exists: false, content: '', sourceNoteTitle: note.title || '' })
+  }
+
+  return NextResponse.json({
+    exists: true,
+    content,
+    sourceNoteTitle: note.title || 'Sans titre',
+  })
+}