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/components/mobile-nav.tsx

@@ -1,7 +1,6 @@
 "use client";
 
-import { AnimatePresence, motion } from "motion/react";
-import Image from "next/image";
+import dynamic from "next/dynamic";
 import {
 	type ReactNode,
 	useCallback,
@@ -10,7 +9,11 @@ import {
 	useRef,
 	useState,
 } from "react";
-import { mobileMenuVariants } from "@/lib/motion";
+
+/** Lazily loaded so `motion/react` is not in the public pages' initial JS. */
+const MobileNavPanel = dynamic(() => import("@/components/mobile-nav-panel"), {
+	ssr: false,
+});
 
 interface MobileNavProps {
 	children: ReactNode;
@@ -129,16 +132,16 @@ export function MobileNav({
 				aria-haspopup="dialog"
 				aria-controls={menuId}
 			>
-				<motion.svg
-					className="w-6 h-6"
-					animate={{ rotate: open ? 90 : 0 }}
-					transition={{ duration: 0.2 }}
+				<svg
+					className="w-6 h-6 transition-transform duration-200"
+					style={{ transform: open ? "rotate(90deg)" : undefined }}
 					viewBox="0 0 24 24"
 					fill="none"
 					stroke="currentColor"
 					strokeWidth="2"
 					strokeLinecap="round"
 					strokeLinejoin="round"
+					aria-hidden="true"
 				>
 					{open ? (
 						<>
@@ -152,67 +155,18 @@ export function MobileNav({
 							<line x1="4" y1="17" x2="20" y2="17" />
 						</>
 					)}
-				</motion.svg>
+				</svg>
 			</button>
 
-			<AnimatePresence>
-				{open && (
-					<motion.div
-						id={menuId}
-						role="dialog"
-						aria-modal="true"
-						aria-label={brandLabel || "Navigation menu"}
-						className="absolute left-0 top-full mt-2 w-[min(88vw,360px)] z-50 origin-top-left"
-						style={{ backgroundColor: "transparent" }}
-						variants={mobileMenuVariants}
-						initial="hidden"
-						animate="visible"
-						exit="exit"
-					>
-						<div
-							ref={menuRef}
-							className="flex flex-col gap-y-1 p-2 rounded-2xl border shadow-xl max-h-[calc(100dvh-5rem)] overflow-y-auto overscroll-contain
-							bg-[var(--color-dropdown,var(--color-surface,#fff))]"
-							style={{
-								borderColor:
-									"color-mix(in srgb, var(--color-text-muted) 12%, transparent)",
-								boxShadow:
-									"0 12px 40px color-mix(in srgb, rgb(0 0 0) 22%, transparent)",
-							}}
-						>
-							<div
-								className="flex items-center gap-2 px-3 py-2 mb-1 rounded-xl"
-								style={{
-									backgroundColor:
-										"color-mix(in srgb, var(--color-primary) 12%, transparent)",
-								}}
-							>
-								<Image
-									src="/assets/images/icons/navigation/home.png"
-									alt=""
-									width={22}
-									height={22}
-									className="shrink-0"
-								/>
-								<span
-									className="text-sm font-extrabold uppercase tracking-wide"
-									style={{
-										color:
-											"var(--color-navbar-text-readable, var(--color-text))",
-									}}
-								>
-									{brandLabel}
-								</span>
-								<span className="ml-auto text-[11px] font-semibold uppercase tracking-wider opacity-75">
-									{closeLabel}
-								</span>
-							</div>
-
-							{children}
-						</div>
-					</motion.div>
-				)}
-			</AnimatePresence>
+			<MobileNavPanel
+				open={open}
+				menuId={menuId}
+				menuRef={menuRef}
+				brandLabel={brandLabel}
+				closeLabel={closeLabel}
+			>
+				{children}
+			</MobileNavPanel>
 		</div>
 	);
 }