Add dark mode, i18n, messenger/moderation/verify, admin CRUD parity

Web-tier features completing the AtomCMS→Next.js conversion (slice 2):

UI/UX:
- Dark mode: html.dark CSS-var overrides + ThemeSwitcher (localStorage,
  no-flash boot script) wired into the nav.
- i18n (next-intl, cookie-based / no URL routing): en + it catalogs,
  request.ts, provider in root layout, LanguageSwitcher; shell (nav,
  header, footer) fully translated. URLs + access-guard unchanged.
- globals.css: --muted/--border aliases used across admin pages.

User features:
- /messages: offline messages + friend-request accept (server action
  re-reads session, two directional rows, idempotent).
- Email verification: signed-token /verify route + sendVerification wired
  into register (best-effort, never blocks signup).
- Article reactions: toggle UI on news/[slug] + server action.
- Content moderation service (website_wordfilter + optional OpenAI
  moderations, fail-open) wired into article comments + guestbook.

Admin CRUD parity (Filament replacement):
- /admin/shop (+ new/[id]) packages CRUD + read-only orders.
- /admin/transactions read-only PayPal log.
- /admin/permissions, /admin/tags, /admin/ads (+ new/[id]),
  /admin/help-questions (+ new/[id]), /admin/radio/history,
  /admin/users/[id]/edit. All gated by requireStaff + logStaffActivity.

Verified: tsc 0, vitest 48/48, next build 0 (all routes incl. new
admin CRUD + /messages + /verify).

src/app/admin/ads/page.tsx

@@ -0,0 +1,60 @@
+import Link from "next/link";
+import { prisma } from "@/lib/prisma";
+
+export const dynamic = "force-dynamic";
+
+export default async function AdminAds() {
+  let ads: Awaited<ReturnType<typeof prisma.websiteAds.findMany>> = [];
+  try {
+    ads = await prisma.websiteAds.findMany({
+      orderBy: { id: "desc" },
+      take: 500,
+    });
+  } catch {
+    ads = [];
+  }
+
+  return (
+    <main>
+      <div style={{ display: "flex", alignItems: "center", gap: "1rem" }}>
+        <h1 style={{ flex: 1 }}>Advertisements</h1>
+        <Link href="/admin/ads/new">+ New ad</Link>
+      </div>
+      <p className="muted">
+        Website advertisement banners (<code>website_ads</code>). Each ad is an image URL shown
+        across the site.
+      </p>
+
+      <table>
+        <thead>
+          <tr>
+            <th>Preview</th>
+            <th>Image URL</th>
+            <th>Created</th>
+            <th />
+          </tr>
+        </thead>
+        <tbody>
+          {ads.map((ad) => (
+            <tr key={String(ad.id)}>
+              <td>
+                {/* eslint-disable-next-line @next/next/no-img-element */}
+                <img src={ad.image} alt="" style={{ maxHeight: 40, maxWidth: 120 }} />
+              </td>
+              <td className="muted">
+                <code>{ad.image}</code>
+              </td>
+              <td className="muted">
+                {ad.createdAt ? ad.createdAt.toISOString().slice(0, 10) : ""}
+              </td>
+              <td>
+                <Link href={`/admin/ads/${ad.id}`}>Edit</Link>
+              </td>
+            </tr>
+          ))}
+        </tbody>
+      </table>
+      {ads.length === 0 ? <p className="muted">No advertisements yet.</p> : null}
+    </main>
+  );
+}