feat: harden atoms-nexst against review findings (37 items)

Second review pass covering security, performance, admin tooling and the
public/room flows. All HIGH and MEDIUM findings from the audit are resolved;
nothing in this commit changes the visible feature set.

Authentication & session security
- CSP is now set on the request headers in the proxy, which is what Next.js
  uses to derive the render nonce, so the nonce is effective.
- 2FA: an already-enabled user cannot re-enroll, the setup endpoint is
  rate-limited per account, and confirmed codes are persisted so the second
  secret no longer silently never applies.
- Password reset revokes the ticket, authTicket and all personal access
  tokens, and bumps the token version so existing sessions die. The same
  revocation is now wired into the staff-side password reset.
- /reset and /verify return a stable error code instead of raw text; the
  mail lookups are ordered by id so duplicates cannot vary between runs.
- Resending the verification mail gets a per-address cooldown on top of the
  per-user limit.
- Issue API tokens with the narrower radio/ticket ability set instead of "*".

Authorization & input handling
- Mid-rank staff can no longer keep dynamically granted non-view admin.*
  permissions: existing grants are revoked by migration and the grant lookup
  is restricted to "%.view". Rank guards use the dynamic super-admin check.
- Alerting a user is permission-checked and audited like the other tools.
- Material mutations (giveCredits/giveDuckets/giveDiamonds, the admin user
  actions route, bulk user actions) are capped and rank-guarded, and bulk
  ids are bounded.
- updateRoom / updateRoomItem write through a field allowlist, and items
  may only be edited through their own room.
- Classnames reaching the filesystem are validated before use so a crafted
  value cannot escape the asset directories.
- The word filter now also covers offline mails, guild forum threads and
  replies, and user mottos.
- Media uploads are validated by magic bytes, /api/media requires the page
  edit permission, APP_URL must be configured once mail is enabled, and the
  diagnostics error route checks the fetch site header.

Admin tooling
- Secret settings render masked and cannot be overwritten with a blank or
  an arbitrary raw key; radio credentials are new password inputs.
- Commandocentrum balance changes are audited.
- Admin list pagination reads the caller's per-page instead of the max, and
  the log exporter caps offset and search length.

Performance
- Catalog translations are cached per module, with a cheap revision hash;
  the public online count uses a stale window instead of hammering the DB.
- The cache warmup now primes the payload the home route actually reads.
- TopHeader batches its queries into one round trip, and LCP avatars load
  eagerly.
- motion/react and sonner are no longer part of the root layout; the nav
  dropdown and mobile nav panels are lazy client chunks. Anonymous visitors
  again get the navigation chrome, and public pages get an edge cacheable
  response.

Accessibility
- Nested <main> elements in phase pages became <section>; the page entrance
  and route progress animations are pure CSS that respect reduced motion.

src/app/client/page.tsx

@@ -1,12 +1,11 @@
-import { count, eq } from "drizzle-orm";
 import { headers } from "next/headers";
 import { redirect } from "next/navigation";
 import { auth } from "@/lib/auth";
 import { issueSsoTicket } from "@/lib/auth/sso-ticket";
-import { cached } from "@/lib/cache";
 import { resolveClientIp } from "@/lib/client-ip";
-import { db, User } from "@/lib/db";
 import { resolveHotelName } from "@/lib/hotel-name";
+import { cachedOnlineCount } from "@/lib/services/public-counters";
+
 import { siteSettings } from "@/lib/services/site-settings";
 import { ClientView } from "./client-view";
 
@@ -27,13 +26,7 @@ export default async function ClientPage() {
 	// render as fast as possible since the player is waiting for the game.
 	const [ticket, onlineCount] = await Promise.all([
 		issueSsoTicket(userId, hotelName, ip),
-		cached("online_count", 10_000, async () => {
-			const [row] = await db
-				.select({ total: count() })
-				.from(User)
-				.where(eq(User.online, "1"));
-			return row?.total ?? 0;
-		}).catch(() => 0),
+		cachedOnlineCount().catch(() => 0),
 	]);
 
 	return (