feat: SaaS onboarding, Stripe billing, MFA, SSO, passkeys, refresh tokens

Complete SaaS self-service onboarding sprint:

- Stripe-powered signup flow: pricing page → checkout → provisioning → activation
- Refresh token infrastructure: 1h access tokens + 30-day httpOnly cookie refresh
- TOTP MFA with QR setup, recovery codes, and login challenge flow
- Google + Azure AD SSO (conditional on env vars) with account linking
- WebAuthn passkey registration and passwordless login
- Guided onboarding checklist with server-side progress tracking
- Stubbed email service (console + DB logging, ready for real provider)
- Settings page with tabbed security settings (MFA, passkeys, linked accounts)
- Login page enhanced with MFA verification, SSO buttons, passkey login
- Database migration 015 with all new tables and columns
- Version bump to 2026.03.17

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

backend/src/modules/auth/auth.module.ts

@@ -4,8 +4,15 @@ import { PassportModule } from '@nestjs/passport';
 import { ConfigModule, ConfigService } from '@nestjs/config';
 import { AuthController } from './auth.controller';
 import { AdminController } from './admin.controller';
+import { MfaController } from './mfa.controller';
+import { SsoController } from './sso.controller';
+import { PasskeyController } from './passkey.controller';
 import { AuthService } from './auth.service';
 import { AdminAnalyticsService } from './admin-analytics.service';
+import { RefreshTokenService } from './refresh-token.service';
+import { MfaService } from './mfa.service';
+import { SsoService } from './sso.service';
+import { PasskeyService } from './passkey.service';
 import { JwtStrategy } from './strategies/jwt.strategy';
 import { LocalStrategy } from './strategies/local.strategy';
 import { UsersModule } from '../users/users.module';
@@ -21,12 +28,27 @@ import { OrganizationsModule } from '../organizations/organizations.module';
       inject: [ConfigService],
       useFactory: (configService: ConfigService) => ({
         secret: configService.get<string>('JWT_SECRET'),
-        signOptions: { expiresIn: '24h' },
+        signOptions: { expiresIn: '1h' },
       }),
     }),
   ],
-  controllers: [AuthController, AdminController],
-  providers: [AuthService, AdminAnalyticsService, JwtStrategy, LocalStrategy],
-  exports: [AuthService],
+  controllers: [
+    AuthController,
+    AdminController,
+    MfaController,
+    SsoController,
+    PasskeyController,
+  ],
+  providers: [
+    AuthService,
+    AdminAnalyticsService,
+    RefreshTokenService,
+    MfaService,
+    SsoService,
+    PasskeyService,
+    JwtStrategy,
+    LocalStrategy,
+  ],
+  exports: [AuthService, RefreshTokenService, JwtModule],
 })
 export class AuthModule {}