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.

drizzle/migrations/0034_acl_midrank_revoke.sql

@@ -0,0 +1,25 @@
+-- Repair the escalation introduced by 0018's rule 1 ("has admin.dashboard gets
+-- ALL admin.*"). Migrating 0011 grants admin.dashboard to every rank >= 6 so
+-- that the sidebar opens, which meant rank 6 silently acquired
+-- admin.permissions.manage, admin.rcon.execute, admin.settings.edit,
+-- admin.users.edit, admin.users.reset_password, admin.room.delete, ...
+--
+-- Rule 1 is narrowed to `admin.%.view` (read-only, all the sidebar needs) in
+-- both the migration set and the runtime repair action. This migration undoes
+-- the over-grant on databases that already ran 0018: every role below the top
+-- rank keeps dashboard + *.view and loses every other admin.* grant. Ranks
+-- that legitimately hold tools keep them, because rule 3 only targets
+-- rank >= 7 and those roles are not touched here.
+
+DELETE `amp`
+FROM `acl_model_permissions` `amp`
+JOIN `acl_roles` `ar`
+  ON `ar`.`id` = `amp`.`model_id`
+ AND `ar`.`model_type` = 'Role'
+ AND `amp`.`model_type` = 'Role'
+JOIN `acl_permissions` `ap`
+  ON `ap`.`id` = `amp`.`permission_id`
+WHERE `ap`.`slug` LIKE 'admin.%'
+  AND `ap`.`slug` NOT LIKE '%.view'
+  AND `ar`.`slug` REGEXP '^rank_[0-9]+$'
+  AND CAST(SUBSTRING(`ar`.`slug`, 7) AS UNSIGNED) < 7;