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/routes/player/PlayerLogin.jsx

@@ -1,6 +1,7 @@
 import { useEffect, useState } from 'react'
 import { Link, useNavigate, useLocation } from 'react-router-dom'
 import ProviderIcon from '../../components/ProviderIcon.jsx'
+import TrustLimitModal from '../../components/security/TrustLimitModal.jsx'
 import { useAuth } from '../../contexts/AuthContext.jsx'
 import { api } from '../../api/client.js'
 import PlayerShell, { honeypotStyle } from './PlayerShell.jsx'
@@ -34,6 +35,12 @@ export default function PlayerLogin() {
   const [challenge, setChallenge] = useState('')
   const [code, setCode] = useState('')
   const [ssoTotp, setSsoTotp] = useState(false)
+  const [trustDevice, setTrustDevice] = useState(false)
+  const [useRecovery, setUseRecovery] = useState(false)
+  // When trust was requested at login but the device cap is reached: show the
+  // revoke-to-continue modal, then navigate on resolve. `pendingDest` holds where
+  // to go once the prompt is dealt with.
+  const [trustLimit, setTrustLimit] = useState(null) // { devices, dest }
 
   const [providers, setProviders] = useState([])
   const [canRegister, setCanRegister] = useState(false)
@@ -111,12 +118,25 @@ export default function PlayerLogin() {
         }
         navigate(returnTo || '/account', { replace: true })
       } else {
-        const u = await loginTotp(challenge, code)
-        navigate(destFor(u), { replace: true })
+        const entered = code.trim()
+        const data = await loginTotp(challenge, useRecovery ? '' : entered, {
+          recoveryCode: useRecovery ? entered : undefined,
+          trustDevice,
+        })
+        const to = destFor(data.user)
+        // Trust was requested but the device cap is reached: the session is already
+        // issued, so prompt to revoke one before trusting, then navigate.
+        if (data.trustLimitReached) {
+          setTrustLimit({ devices: data.devices || [], dest: to })
+          setBusy(false)
+          return
+        }
+        navigate(to, { replace: true })
       }
     } catch (err) {
       const expired = err.status === 401 && /expired/i.test(err.message)
-      setError(expired ? 'Your verification session expired. Please sign in again.' : 'Invalid verification code.')
+      const badRecovery = useRecovery ? 'That recovery code is not valid.' : 'Invalid verification code.'
+      setError(expired ? 'Your verification session expired. Please sign in again.' : badRecovery)
       setBusy(false)
       if (expired) {
         setStage('creds')
@@ -169,13 +189,42 @@ export default function PlayerLogin() {
             </div>
           </>
         ) : (
-          <label style={{ display: 'block', marginBottom: 22 }}>
-            <span className="field-label">Authentication code</span>
-            <input type="text" inputMode="numeric" autoComplete="one-time-code" autoFocus placeholder="6-digit code" value={code} onChange={(e) => setCode(e.target.value)} className="input" />
-            <span className="sans" style={{ display: 'block', marginTop: 8, color: 'var(--dim)', fontSize: '0.76rem' }}>
-              Enter the code from your authenticator app.
-            </span>
-          </label>
+          <>
+            <label style={{ display: 'block', marginBottom: 14 }}>
+              <span className="field-label">{useRecovery ? 'Recovery code' : 'Authentication code'}</span>
+              <input
+                type="text"
+                inputMode={useRecovery ? 'text' : 'numeric'}
+                autoComplete="one-time-code"
+                autoFocus
+                placeholder={useRecovery ? 'xxxxx-xxxxx' : '6-digit code'}
+                value={code}
+                onChange={(e) => setCode(e.target.value)}
+                className="input"
+              />
+              <span className="sans" style={{ display: 'block', marginTop: 8, color: 'var(--dim)', fontSize: '0.76rem' }}>
+                {useRecovery ? 'Enter one of your saved single-use recovery codes.' : 'Enter the code from your authenticator app.'}
+              </span>
+            </label>
+            {/* Trust-this-device only applies to real authenticator/recovery login,
+                not the SSO 2FA bounce (which has no trust cookie flow here). */}
+            {!ssoTotp && (
+              <label className="sans" style={{ display: 'flex', alignItems: 'center', gap: 8, marginBottom: 12, color: 'var(--muted)', fontSize: '0.84rem' }}>
+                <input type="checkbox" checked={trustDevice} onChange={(e) => setTrustDevice(e.target.checked)} />
+                Trust this device for 30 days (skip the code next time)
+              </label>
+            )}
+            {!ssoTotp && (
+              <button
+                type="button"
+                onClick={() => { setUseRecovery((v) => !v); setCode('') }}
+                className="sans"
+                style={{ display: 'block', marginBottom: 22, background: 'none', border: 'none', padding: 0, color: 'var(--accent)', cursor: 'pointer', fontSize: '0.8rem' }}
+              >
+                {useRecovery ? 'Use an authenticator code instead' : 'Use a recovery code instead'}
+              </button>
+            )}
+          </>
         )}
 
         {(error || (stage === 'creds' && ssoError)) && (
@@ -208,6 +257,14 @@ export default function PlayerLogin() {
           </div>
         )}
       </form>
+
+      {trustLimit && (
+        <TrustLimitModal
+          devices={trustLimit.devices}
+          onTrusted={() => navigate(trustLimit.dest, { replace: true })}
+          onCancel={() => navigate(trustLimit.dest, { replace: true })}
+        />
+      )}
     </PlayerShell>
   )
 }