feat: publication pages — design moderne + modération IA + signalement

Page publique (/p/[slug]):
- Design éditorial moderne (Source Serif 4 + Inter, couleurs Momento)
- KaTeX rendu côté serveur (plus de 3184089 en brut)
- Callouts colorés, toggles, colonnes, code blocks rendus correctement
- Barre sticky avec logo + bouton Signaler
- Temps de lecture estimé
- Footer Momento
- Responsive

Modération:
- content-moderation.service.ts — IA classe safe/flagged/blocked
- Sera appelée automatiquement à la publication

Signalement:
- Page /p/[slug]/report — formulaire de signalement public
- API /api/notes/report — stocke notification au propriétaire + admins
- 8 motifs: illegal, haine, violence, sexuel, harcèlement, copyright, spam, autre

i18n: FR/EN

memento-note/app/api/notes/report/route.ts

@@ -0,0 +1,51 @@
+import { NextRequest, NextResponse } from 'next/server'
+import prisma from '@/lib/prisma'
+
+export async function POST(request: NextRequest) {
+  try {
+    const { slug, reason, details } = await request.json()
+    if (!slug || !reason) {
+      return NextResponse.json({ error: 'slug and reason required' }, { status: 400 })
+    }
+
+    const note = await prisma.note.findFirst({
+      where: { publicSlug: slug, isPublic: true },
+      select: { id: true, userId: true },
+    })
+    if (!note) return NextResponse.json({ error: 'Note not found' }, { status: 404 })
+
+    // Store as a notification to the note owner + admin
+    await prisma.notification.create({
+      data: {
+        userId: note.userId,
+        type: 'content_report',
+        title: `Signalement : ${reason}`,
+        message: details || `Un visiteur a signalé votre note publiée pour: ${reason}`,
+        actionUrl: `/p/${slug}`,
+        relatedId: note.id,
+      },
+    }).catch(() => {})
+
+    // Also notify admins
+    const admins = await prisma.user.findMany({
+      where: { role: 'ADMIN' },
+      select: { id: true },
+    })
+    for (const admin of admins) {
+      await prisma.notification.create({
+        data: {
+          userId: admin.id,
+          type: 'content_report',
+          title: `Signalement de contenu : ${reason}`,
+          message: `Note /p/${slug} signalée pour: ${reason}${details ? ` — ${details}` : ''}`,
+          actionUrl: `/admin/published`,
+          relatedId: note.id,
+        },
+      }).catch(() => {})
+    }
+
+    return NextResponse.json({ success: true })
+  } catch (error: any) {
+    return NextResponse.json({ error: error.message }, { status: 500 })
+  }
+}