feat: add contact page with form handling and validation

- Implemented a contact page with a form for user inquiries.
- Added validation for form fields using Zod schema.
- Integrated PostgreSQL database for storing contact messages.
- Created necessary API endpoints for form submission.
- Added admin authentication and session management.
- Developed CGU, cookies policy, privacy policy, and legal mentions pages.
- Set up Docker configuration for PostgreSQL and application services.
- Enhanced UI with responsive design and accessibility features.

app/api/admin/messages/[id]/status/route.ts

@@ -0,0 +1,33 @@
+import { NextResponse } from "next/server";
+import { isAdminAuthenticated } from "@/lib/admin-auth";
+import { setMessageStatus } from "@/lib/db";
+
+export async function POST(
+  request: Request,
+  context: { params: Promise<{ id: string }> },
+) {
+  const authenticated = await isAdminAuthenticated();
+  if (!authenticated) {
+    return NextResponse.json({ message: "Unauthorized" }, { status: 401 });
+  }
+
+  const { id } = await context.params;
+  const messageId = Number(id);
+  if (!Number.isInteger(messageId) || messageId <= 0) {
+    return NextResponse.json({ message: "ID invalide." }, { status: 400 });
+  }
+
+  const body = (await request.json().catch(() => null)) as { status?: string } | null;
+  const status = body?.status;
+
+  if (status !== "pending" && status !== "replied") {
+    return NextResponse.json({ message: "Statut invalide." }, { status: 400 });
+  }
+
+  const updated = await setMessageStatus(messageId, status);
+  if (!updated) {
+    return NextResponse.json({ message: "Message introuvable." }, { status: 404 });
+  }
+
+  return NextResponse.json({ ok: true });
+}