feat(auth): trusted devices, recovery codes, and admin MFA management

Add opt-in "Trust this device" so a browser/app skips the TOTP step (never
the password) for 30 days, single-use bcrypt recovery codes as a 2FA-lockout
fallback, and admin trusted-device/MFA-reset management — backend, web UI,
OpenAPI spec, and tests.

- Schema: trusted_devices (sha256 token hash, looked up by unique index) and
  recovery_codes (bcrypt, single-use). Both additive/idempotent.
- Session service: trust-token mint/hash/resolve + cap helpers; new rg_trust
  httpOnly cookie (survives logout, revoked on untrust/password change/reset/
  TOTP disable). JWTs stay stateless — trust is a server-side row, not a claim.
- Web + mobile login accept a trusted-device token / recovery code; login/totp
  gains trustDevice + recoveryCode. Cap of 10/user with NO silent pruning — an
  over-cap trust returns 409/trustLimitReached and the client prompts to revoke.
- Self-service /auth/me/trusted-devices* + recovery-codes*; admin
  /admin/users/:id/trusted-devices* + /mfa/reset. All actions audit-logged.
- Client: "Trust this device" + recovery-code login options, one-time recovery
  code display, Trusted Devices + Recovery Codes account panels, a TOTP-styled
  revoke-to-continue cap modal, and admin per-user security controls.
- OpenAPI regenerated; 33 new server tests (all suites green).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

client/src/api/client.js

@@ -56,8 +56,12 @@ export const api = {
   getInvite: (token) => req(`/auth/invite/${encodeURIComponent(token)}`),
   acceptInvite: (token, username, password, extra = {}) =>
     req(`/auth/invite/${encodeURIComponent(token)}/accept`, { method: 'POST', body: { username, password, ...extra } }),
-  loginTotp: (challenge, code) =>
-    req('/auth/login/totp', { method: 'POST', body: { challenge, code } }),
+  // Second factor for web login. `extra` carries the optional recoveryCode (an
+  // alternative to code) and the trustDevice/deviceName opt-in. On success the
+  // response may include { trustLimitReached, devices } when trust was requested
+  // but the device cap is reached.
+  loginTotp: (challenge, code, extra = {}) =>
+    req('/auth/login/totp', { method: 'POST', body: { challenge, code, ...extra } }),
   // Self-service password reset (public, token-gated). forgot always resolves the
   // same way whether or not the email exists (no enumeration); getPasswordReset
   // validates a link (200 → { username }, 404 → invalid/expired); resetPassword
@@ -76,6 +80,20 @@ export const api = {
   // List the active ones and revoke a single device by its session id.
   mySessions: () => req('/auth/me/sessions'),
   revokeMySession: (id) => req(`/auth/me/sessions/${encodeURIComponent(id)}`, { method: 'DELETE' }),
+  // Trusted devices (MFA "Trust this device"), role-agnostic under /auth/me. These
+  // are the browsers/apps allowed to skip the TOTP step at login (distinct from
+  // mySessions, which are live mobile login sessions).
+  myTrustedDevices: () => req('/auth/me/trusted-devices'),
+  trustThisDevice: (deviceName) =>
+    req('/auth/me/trusted-devices', { method: 'POST', body: { deviceName } }),
+  revokeTrustedDevice: (id) =>
+    req(`/auth/me/trusted-devices/${encodeURIComponent(id)}`, { method: 'DELETE' }),
+  revokeAllTrustedDevices: () => req('/auth/me/trusted-devices', { method: 'DELETE' }),
+  // Recovery (backup) codes. status → remaining count; generate → a fresh set,
+  // returned ONCE (password step-up for accounts that have a password).
+  recoveryCodesStatus: () => req('/auth/me/account/recovery-codes/status'),
+  generateRecoveryCodes: (currentPassword) =>
+    req('/auth/me/account/recovery-codes/generate', { method: 'POST', body: { currentPassword } }),
 
   // ----- public -----
   publicSettings: () => req('/public/settings'),
@@ -199,6 +217,13 @@ export const api = {
     createUser: (data) => req('/admin/users', { method: 'POST', body: data }),
     updateUser: (id, data) => req(`/admin/users/${id}`, { method: 'PUT', body: data }),
     deleteUser: (id) => req(`/admin/users/${id}`, { method: 'DELETE' }),
+    // A user's trusted devices + MFA reset (admin only).
+    userTrustedDevices: (id) => req(`/admin/users/${id}/trusted-devices`),
+    revokeUserTrustedDevice: (id, deviceId) =>
+      req(`/admin/users/${id}/trusted-devices/${deviceId}`, { method: 'DELETE' }),
+    revokeAllUserTrustedDevices: (id) =>
+      req(`/admin/users/${id}/trusted-devices`, { method: 'DELETE' }),
+    resetUserMfa: (id) => req(`/admin/users/${id}/mfa/reset`, { method: 'POST' }),
     // Email invites.
     listInvites: () => req('/admin/invites'),
     createInvite: (email, role, sendEmail = true) =>