feat(account): self-service account deletion, MODULE_API 1.20.0

ACCOUNT_DELETION.md phase 2 (core): a member deletes their own account on
the website, and the admin route runs the same procedure.

- DELETE /api/v1/auth/me/account: typed username, password always (AD7),
  and a 2FA or recovery code when 2FA is on. A wrong password or code is
  400, not 401 (AD12), so the app's refresh-on-401 never replays it.
  409 password_required and last_admin; the demo's shared logins are
  locked.
- auth/accountDeletion.js: module hooks first, then one transaction that
  reserves a staff username (reserved_usernames, AD9) and deletes the row,
  then a Teams reconcile, the audit entry (no username) and a notice to
  the old address (new protected template auth.account-deleted).
- MODULE_API 1.20.0: api.onUserDeleting({ userId, deletedBy }), before the
  delete, 10 s limit, cannot veto (AD10, AD11).
- utils/displayAuthor.js: a deleted account's username snapshots read
  "[deleted player]" to members and the stored name, marked, to staff
  (AD5, AD6). Used by the forum, the Reports queue, the guest list and
  the Team digest. A deleted account drops off Forum guests (AD13).
- Reserved names refuse at every username write, answered as "taken".
- Web: Delete my account on the player and staff Account pages; staff
  views mark "(deleted account)".
- OpenAPI regenerated; route manifest and engagement manifest regenerated.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01E14m6SuuY6i1vASFeGDBeY

client/src/routes/player/PlayerAccount.jsx

@@ -5,6 +5,7 @@ import RecoveryCodesDisplay from '../../components/security/RecoveryCodesDisplay
 import TrustedDevicesPanel from '../../components/security/TrustedDevicesPanel.jsx'
 import RecoveryCodesPanel from '../../components/security/RecoveryCodesPanel.jsx'
 import EmailAddressPanel from '../../components/security/EmailAddressPanel.jsx'
+import DeleteAccountPanel from '../../components/security/DeleteAccountPanel.jsx'
 import { IdentitySummary, linkBanner, linkableProviders, unlinkPrompt } from '../../components/security/linkedIdentities.jsx'
 import { useAuth } from '../../contexts/AuthContext.jsx'
 import { api } from '../../api/client.js'
@@ -422,6 +423,7 @@ export default function PlayerAccount() {
           )}
           <LinkedAccounts />
           <ActiveDevices />
+          <DeleteAccountPanel account={account} />
         </>
       )}
     </div>