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-panel.tsx

@@ -0,0 +1,86 @@
+"use client";
+
+import { AnimatePresence, motion } from "motion/react";
+import Image from "next/image";
+import type { ReactNode } from "react";
+import { mobileMenuVariants } from "@/lib/motion";
+
+/**
+ * Animated mobile menu sheet, split out of `MobileNav` so `motion/react` only
+ * ships once the hamburger menu is opened instead of on every public page.
+ */
+export default function MobileNavPanel({
+	open,
+	menuId,
+	menuRef,
+	brandLabel,
+	closeLabel,
+	children,
+}: {
+	open: boolean;
+	menuId: string;
+	menuRef: React.RefObject<HTMLDivElement | null>;
+	brandLabel: string;
+	closeLabel: string;
+	children: ReactNode;
+}) {
+	return (
+		<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>
+			) : null}
+		</AnimatePresence>
+	);
+}