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/users/[id]/edit/page.tsx

@@ -0,0 +1,145 @@
+import Link from "next/link";
+import { notFound } from "next/navigation";
+import { updateUser } from "@/actions/admin-user-edit";
+import { requireStaff } from "@/lib/admin/guard";
+import { prisma } from "@/lib/prisma";
+
+export const dynamic = "force-dynamic";
+
+// users_currency.type values for the non-credits currencies (see send-currency.ts).
+const DUCKETS_TYPE = 0;
+const DIAMONDS_TYPE = 5;
+
+export default async function AdminUserEdit({
+  params,
+}: {
+  params: Promise<{ id: string }>;
+}) {
+  // Gate the page with the SAME helper the action re-checks.
+  await requireStaff();
+
+  const { id } = await params;
+  const userId = Number(id);
+  if (!Number.isInteger(userId) || userId <= 0) notFound();
+
+  let user: {
+    id: number;
+    username: string;
+    mail: string | null;
+    motto: string;
+    look: string;
+    rank: number;
+    credits: number;
+    pixels: number;
+    points: number;
+  } | null = null;
+  let duckets = 0;
+  let diamonds = 0;
+
+  try {
+    user = await prisma.user.findUnique({
+      where: { id: userId },
+      select: {
+        id: true,
+        username: true,
+        mail: true,
+        motto: true,
+        look: true,
+        rank: true,
+        credits: true,
+        pixels: true,
+        points: true,
+      },
+    });
+    if (user) {
+      const currencies = await prisma.usersCurrency.findMany({
+        where: { userId, type: { in: [DUCKETS_TYPE, DIAMONDS_TYPE] } },
+        select: { type: true, amount: true },
+      });
+      for (const c of currencies) {
+        if (c.type === DUCKETS_TYPE) duckets = c.amount;
+        else if (c.type === DIAMONDS_TYPE) diamonds = c.amount;
+      }
+    }
+  } catch {
+    return (
+      <main>
+        <p className="muted">
+          <Link href="/admin/users">← Users</Link>
+        </p>
+        <h1>Edit user</h1>
+        <p className="muted">Could not load this user right now. Try again shortly.</p>
+      </main>
+    );
+  }
+
+  if (!user) notFound();
+
+  return (
+    <main>
+      <p className="muted">
+        <Link href={`/admin/users/${user.id}`}>← {user.username}</Link>
+      </p>
+      <h1>Edit {user.username}</h1>
+      <p className="muted">ID {user.id}</p>
+
+      <form action={updateUser} className="card">
+        <input type="hidden" name="id" value={user.id} />
+
+        <div className="grid cols-2">
+          <label>
+            Email
+            <input name="mail" type="email" defaultValue={user.mail ?? ""} maxLength={500} />
+          </label>
+
+          <label>
+            Rank
+            <input name="rank" type="number" min={1} defaultValue={user.rank} />
+          </label>
+
+          <label>
+            Motto
+            <input name="motto" defaultValue={user.motto} maxLength={127} />
+          </label>
+
+          <label>
+            Look
+            <input name="look" defaultValue={user.look} maxLength={256} />
+          </label>
+
+          <label>
+            Credits
+            <input name="credits" type="number" min={0} defaultValue={user.credits} />
+          </label>
+
+          <label>
+            Pixels
+            <input name="pixels" type="number" min={0} defaultValue={user.pixels} />
+          </label>
+
+          <label>
+            Points
+            <input name="points" type="number" min={0} defaultValue={user.points} />
+          </label>
+
+          <label>
+            Duckets
+            <input name="duckets" type="number" min={0} defaultValue={duckets} />
+          </label>
+
+          <label>
+            Diamonds
+            <input name="diamonds" type="number" min={0} defaultValue={diamonds} />
+          </label>
+        </div>
+
+        <p className="muted">Currency fields set the exact balance, not a delta. Passwords are not editable here.</p>
+
+        <div style={{ display: "flex", gap: "0.5rem", marginTop: "0.5rem" }}>
+          <button type="submit" className="btn btn-primary">Save changes</button>
+          <Link href={`/admin/users/${user.id}`} className="btn">Cancel</Link>
+        </div>
+      </form>
+    </main>
+  );
+}