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/help-questions/page.tsx

@@ -0,0 +1,59 @@
+import Link from "next/link";
+import { prisma } from "@/lib/prisma";
+
+export const dynamic = "force-dynamic";
+
+export default async function AdminHelpQuestions() {
+  let entries: Awaited<
+    ReturnType<typeof prisma.websiteHelpCenterCategories.findMany>
+  > = [];
+  try {
+    entries = await prisma.websiteHelpCenterCategories.findMany({
+      orderBy: [{ position: "asc" }, { id: "asc" }],
+      take: 500,
+    });
+  } catch {
+    entries = [];
+  }
+
+  return (
+    <main>
+      <div style={{ display: "flex", alignItems: "center", gap: "1rem" }}>
+        <h1 style={{ flex: 1 }}>Help Center</h1>
+        <Link href="/admin/help-questions/new">+ New entry</Link>
+      </div>
+      <p className="muted">
+        Help-center FAQ entries (<code>website_help_center_categories</code>). Shown to visitors on
+        the public help page, ordered by position.
+      </p>
+
+      <table>
+        <thead>
+          <tr>
+            <th>Pos.</th>
+            <th>Name</th>
+            <th>Button</th>
+            <th>Small box</th>
+            <th />
+          </tr>
+        </thead>
+        <tbody>
+          {entries.map((e) => (
+            <tr key={String(e.id)}>
+              <td className="muted">{e.position}</td>
+              <td>
+                <Link href={`/admin/help-questions/${e.id}`}>{e.name}</Link>
+              </td>
+              <td className="muted">{e.buttonText || "—"}</td>
+              <td className="muted">{e.smallBox ? "Yes" : "No"}</td>
+              <td>
+                <Link href={`/admin/help-questions/${e.id}`}>Edit</Link>
+              </td>
+            </tr>
+          ))}
+        </tbody>
+      </table>
+      {entries.length === 0 ? <p className="muted">No help-center entries yet.</p> : null}
+    </main>
+  );
+}