audit: 33-agent comprehensive audit + critical fixes

Full team audit run, all reports verbatim in docs/AUDIT-2026-05-12.md
(5900+ lines, 30+ critical findings). Already-fixed this commit:
- permission-overrides PUT: self-target block + RolePermissions allow-list + cross-tenant guard
- /api/auth/resolve-identifier: rate-limit + synthetic miss-email kill enumeration
- admin email-change: rotates account.accountId + revokes sessions
- middleware: token-gated email confirm/cancel routes whitelisted
- NAV_CATALOG: 10 dead-link sweeps to existing /admin/<x> targets

Feature work landing same commit: optional username sign-in
(migration 0054), per-user permission overrides (0055) with three-state
matrix tabbed inside UserForm, user disable button, role + outcome +
stage label normalisation across the platform, admin email-change
with auto-notification template.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/lib/services/users.service.ts

@@ -1,7 +1,7 @@
 import { and, eq } from 'drizzle-orm';
 
 import { db } from '@/lib/db';
-import { user, userProfiles, userPortRoles, roles, ports } from '@/lib/db/schema';
+import { account, session, user, userProfiles, userPortRoles, roles, ports } from '@/lib/db/schema';
 import { auth } from '@/lib/auth';
 import { createAuditLog, type AuditMeta } from '@/lib/audit';
 import { ConflictError, NotFoundError, ValidationError } from '@/lib/errors';
@@ -247,6 +247,25 @@ export async function updateUser(
     await db.update(user).set(userUpdates).where(eq(user.id, userId));
   }
 
+  if (wantsEmailChange) {
+    const newEmailLower = data.email!.toLowerCase();
+    // Better Auth's credential provider authenticates by
+    // `account.accountId` (the email captured at sign-up), NOT by
+    // `user.email`. Without this update the user can't sign in with
+    // either address — old fails because user.email no longer matches,
+    // new fails because there's no account.accountId row for it.
+    await db
+      .update(account)
+      .set({ accountId: newEmailLower, updatedAt: new Date() })
+      .where(and(eq(account.userId, userId), eq(account.providerId, 'credential')));
+
+    // Revoke every active session — the admin just changed the identity
+    // the user authenticates with, so existing sessions are effectively
+    // orphaned and a security risk if the account is being rotated due
+    // to compromise. The user re-authenticates with the new address.
+    await db.delete(session).where(eq(session.userId, userId));
+  }
+
   if (wantsEmailChange && previousEmail) {
     // Best-effort notification — failure to send doesn't roll back the
     // change because Better Auth's primary identity has already moved.