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/components/theme-switcher.tsx

@@ -0,0 +1,42 @@
+"use client";
+
+import { useEffect, useState } from "react";
+
+/**
+ * Light/dark toggle. The actual class lives on <html> (so `.app.dark` selectors
+ * and the dark CSS-var block apply); we mirror localStorage so the choice
+ * survives reloads. The inline boot script in the root layout applies the saved
+ * theme before paint to avoid a flash — this component only reflects/toggles it.
+ */
+export function ThemeSwitcher() {
+  const [dark, setDark] = useState(false);
+
+  useEffect(() => {
+    setDark(document.documentElement.classList.contains("dark"));
+  }, []);
+
+  function toggle() {
+    const next = !dark;
+    setDark(next);
+    document.documentElement.classList.toggle("dark", next);
+    try {
+      localStorage.setItem("theme", next ? "dark" : "light");
+    } catch {
+      /* private mode / storage disabled — runtime toggle still works */
+    }
+  }
+
+  return (
+    <button
+      type="button"
+      onClick={toggle}
+      className="nav-item cursor-pointer"
+      aria-label={dark ? "Switch to light mode" : "Switch to dark mode"}
+      title={dark ? "Light mode" : "Dark mode"}
+    >
+      <span aria-hidden className="text-lg leading-none">
+        {dark ? "☀" : "☾"}
+      </span>
+    </button>
+  );
+}