feat: dashboard Second Brain, essai 7 jours et vérification e-mail

Rendre le dashboard actionnable (inbox, peek, carte mentale), aligner la facturation sur l’essai 7 jours, et bloquer le login e-mail tant que l’adresse n’est pas confirmée.

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

memento-note/app/api/billing/webhook/route.ts

@@ -12,6 +12,8 @@ import {
   isCreditPackId,
   resolvePackFromPriceId,
 } from '@/lib/billing/credit-packs';
+import { sendTrialEndingReminder } from '@/lib/billing/trial-reminder-email';
+import { prisma } from '@/lib/prisma';
 import type Stripe from 'stripe';
 
 export const runtime = 'nodejs';
@@ -159,6 +161,48 @@ export async function POST(req: NextRequest) {
         break;
       }
 
+      case 'customer.subscription.trial_will_end': {
+        const subscription = event.data.object as Stripe.Subscription;
+        const userId = await resolveUserIdFromStripeEvent(subscription);
+        if (!userId) {
+          console.warn('[billing/webhook] trial_will_end: no userId', subscription.id);
+          break;
+        }
+        const user = await prisma.user.findUnique({
+          where: { id: userId },
+          select: {
+            email: true,
+            name: true,
+            aiSettings: { select: { preferredLanguage: true } },
+          },
+        });
+        if (!user?.email) break;
+
+        await syncSubscriptionFromStripe(subscription, userId);
+
+        const trialEndsAt = subscription.trial_end
+          ? new Date(subscription.trial_end * 1000)
+          : new Date(Date.now() + 3 * 24 * 3600 * 1000);
+
+        const appUrl =
+          process.env.NEXTAUTH_URL?.replace(/\/$/, '') ||
+          process.env.NEXT_PUBLIC_APP_URL?.replace(/\/$/, '') ||
+          'https://memento-note.com';
+
+        const preferred = user.aiSettings?.preferredLanguage ?? 'en';
+        const mailResult = await sendTrialEndingReminder({
+          to: user.email,
+          name: user.name,
+          trialEndsAt,
+          billingUrl: `${appUrl}/settings/billing`,
+          locale: preferred === 'auto' ? 'en' : preferred,
+        });
+        if (!mailResult.success) {
+          console.error('[billing/webhook] trial reminder email failed:', mailResult.error);
+        }
+        break;
+      }
+
       default:
         break;
     }