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/prisma/migrations/20260524110000_add_live_block_ref/migration.sql

@@ -0,0 +1,22 @@
+-- CreateTable
+CREATE TABLE "LiveBlockRef" (
+    "id" TEXT NOT NULL,
+    "sourceNoteId" TEXT NOT NULL,
+    "blockId" TEXT NOT NULL,
+    "targetNoteId" TEXT NOT NULL,
+    "createdAt" TIMESTAMP(3) NOT NULL DEFAULT CURRENT_TIMESTAMP,
+
+    CONSTRAINT "LiveBlockRef_pkey" PRIMARY KEY ("id")
+);
+
+-- CreateIndex
+CREATE INDEX "LiveBlockRef_sourceNoteId_blockId_idx" ON "LiveBlockRef"("sourceNoteId", "blockId");
+
+-- CreateIndex
+CREATE INDEX "LiveBlockRef_targetNoteId_idx" ON "LiveBlockRef"("targetNoteId");
+
+-- AddForeignKey
+ALTER TABLE "LiveBlockRef" ADD CONSTRAINT "LiveBlockRef_sourceNoteId_fkey" FOREIGN KEY ("sourceNoteId") REFERENCES "Note"("id") ON DELETE CASCADE ON UPDATE CASCADE;
+
+-- AddForeignKey
+ALTER TABLE "LiveBlockRef" ADD CONSTRAINT "LiveBlockRef_targetNoteId_fkey" FOREIGN KEY ("targetNoteId") REFERENCES "Note"("id") ON DELETE CASCADE ON UPDATE CASCADE;

memento-note/prisma/migrations/20260524140000_add_note_link/migration.sql

@@ -0,0 +1,26 @@
+-- CreateTable (additive — table may already exist from db push)
+CREATE TABLE IF NOT EXISTS "NoteLink" (
+    "id" TEXT NOT NULL,
+    "sourceNoteId" TEXT NOT NULL,
+    "targetNoteId" TEXT NOT NULL,
+    "contextSnippet" TEXT,
+    "createdAt" TIMESTAMP(3) NOT NULL DEFAULT CURRENT_TIMESTAMP,
+
+    CONSTRAINT "NoteLink_pkey" PRIMARY KEY ("id")
+);
+
+CREATE UNIQUE INDEX IF NOT EXISTS "NoteLink_sourceNoteId_targetNoteId_key" ON "NoteLink"("sourceNoteId", "targetNoteId");
+CREATE INDEX IF NOT EXISTS "NoteLink_sourceNoteId_idx" ON "NoteLink"("sourceNoteId");
+CREATE INDEX IF NOT EXISTS "NoteLink_targetNoteId_idx" ON "NoteLink"("targetNoteId");
+
+DO $$ BEGIN
+  ALTER TABLE "NoteLink" ADD CONSTRAINT "NoteLink_sourceNoteId_fkey" FOREIGN KEY ("sourceNoteId") REFERENCES "Note"("id") ON DELETE CASCADE ON UPDATE CASCADE;
+EXCEPTION
+  WHEN duplicate_object THEN null;
+END $$;
+
+DO $$ BEGIN
+  ALTER TABLE "NoteLink" ADD CONSTRAINT "NoteLink_targetNoteId_fkey" FOREIGN KEY ("targetNoteId") REFERENCES "Note"("id") ON DELETE CASCADE ON UPDATE CASCADE;
+EXCEPTION
+  WHEN duplicate_object THEN null;
+END $$;

memento-note/prisma/schema.prisma

@@ -191,6 +191,8 @@ model Note {
   incomingLinks              NoteLink[]               @relation("TargetLinks")
   clusterMemberships         ClusterMember[]
   bridgeNote                 BridgeNote?
+  sourceLiveBlocks           LiveBlockRef[]           @relation("SourceLiveBlocks")
+  targetLiveBlocks           LiveBlockRef[]           @relation("TargetLiveBlocks")
 
   @@index([isPinned])
   @@index([isArchived])
@@ -201,6 +203,19 @@ model Note {
   @@index([userId, notebookId])
 }
 
+model LiveBlockRef {
+  id             String   @id @default(cuid())
+  sourceNoteId   String
+  blockId        String
+  targetNoteId   String
+  createdAt      DateTime @default(now())
+  sourceNote     Note     @relation("SourceLiveBlocks", fields: [sourceNoteId], references: [id], onDelete: Cascade)
+  targetNote     Note     @relation("TargetLiveBlocks", fields: [targetNoteId], references: [id], onDelete: Cascade)
+
+  @@index([sourceNoteId, blockId])
+  @@index([targetNoteId])
+}
+
 model NoteHistory {
   id         String   @id @default(cuid())
   noteId     String