feat(dashboard): tableau de bord Second Brain configurable avec chargement progressif

Briefing granulaire, pistes rapides puis enrichissement async, layout persisté v5,
suggestions agents, intégration Gmail et navigation sidebar alignée sur /home.

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

memento-note/app/api/cron/agent-suggestions/route.ts

@@ -0,0 +1,41 @@
+import { NextRequest, NextResponse } from 'next/server'
+import prisma from '@/lib/prisma'
+import { agentSuggestionService } from '@/lib/ai/services/agent-suggestion.service'
+
+export const dynamic = 'force-dynamic'
+
+function authorizeCron(request: NextRequest): boolean {
+  const cronSecret = process.env.CRON_SECRET
+  if (!cronSecret) return false
+  const authHeader = request.headers.get('authorization')
+  const bearer = authHeader?.startsWith('Bearer ') ? authHeader.slice(7) : null
+  const querySecret = new URL(request.url).searchParams.get('secret')
+  return bearer === cronSecret || querySecret === cronSecret
+}
+
+/**
+ * POST /api/cron/agent-suggestions
+ * Génère des suggestions d'agents à partir des clusters sémantiques existants.
+ */
+export async function POST(request: NextRequest) {
+  if (!authorizeCron(request)) {
+    return NextResponse.json({ error: 'Unauthorized' }, { status: 401 })
+  }
+
+  const users = await prisma.user.findMany({
+    where: { noteClusters: { some: {} } },
+    select: { id: true },
+    take: 30,
+  })
+
+  let total = 0
+  for (const user of users) {
+    try {
+      total += await agentSuggestionService.generateForUser(user.id)
+    } catch (err) {
+      console.error('[CronAgentSuggestions] user', user.id, err)
+    }
+  }
+
+  return NextResponse.json({ success: true, users: users.length, suggestionsUpserted: total })
+}