fix: remove MFA card from tenant settings, constrain card widths

MFA enrollment now happens during sign-in. Tenant settings page reduced
to: Tenant Details + Auth Policy side-by-side (max 520px each), Passkeys
full-width below.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

ui/src/pages/tenant/SettingsPage.tsx

@@ -15,7 +15,6 @@ import {
   useResetServerAdminPassword,
   useTenantAuthSettings, useUpdateTenantAuthSettings,
 } from '../../api/tenant-hooks';
-import { MfaSection } from '../../components/account/MfaSection';
 import { PasskeySection } from '../../components/account/PasskeySection';
 import { useScopes } from '../../auth/useScopes';
 import styles from '../../styles/platform.module.css';
@@ -140,7 +139,9 @@ export function SettingsPage() {
     <div style={{ padding: 24, display: 'flex', flexDirection: 'column', gap: 20, overflowY: 'auto', flex: 1 }}>
       <h1 style={{ margin: 0, fontSize: '1.25rem', fontWeight: 600 }}>Settings</h1>
 
+      <div style={{ display: 'flex', flexWrap: 'wrap', gap: 20 }}>
         {/* Card 1: Tenant Details */}
+        <div style={{ maxWidth: 520, flex: '1 1 400px' }}>
         <Card title="Tenant Details">
           <div className={styles.dividerList}>
             <div className={styles.kvRow}>
@@ -205,20 +206,16 @@ export function SettingsPage() {
             </form>
           </div>
         </Card>
-
-      {/* Card 2: Multi-Factor Authentication (MFA + Passkeys combined) */}
-      <Card title="Multi-Factor Authentication">
-        <MfaSection bare />
-        <div style={{ borderTop: '1px solid var(--border)', marginTop: 16, paddingTop: 16 }}>
-          <h3 style={{ margin: '0 0 8px', fontSize: '0.875rem', fontWeight: 600, textTransform: 'uppercase', letterSpacing: '0.05em', color: 'var(--text-muted)' }}>
-            Passkeys
-          </h3>
-          <PasskeySection bare />
         </div>
-      </Card>
 
-      {/* Card 3: Authentication Policy (org-wide settings) */}
+        {/* Card 2: Authentication Policy (org-wide settings) */}
+        <div style={{ maxWidth: 520, flex: '1 1 400px' }}>
           <AuthPolicySection />
         </div>
+      </div>
+
+      {/* Card 3: Passkeys (full width) */}
+      <PasskeySection />
+    </div>
   );
 }