feat(auth): add WorkOS and Keycloak SSO providers (rebased) (#220)

Co-authored-by: Jason Woltje <jason@diversecanvas.com>
Co-committed-by: Jason Woltje <jason@diversecanvas.com>

apps/gateway/src/auth/sso.controller.spec.ts

@@ -0,0 +1,40 @@
+import { afterEach, describe, expect, it, vi } from 'vitest';
+import { SsoController } from './sso.controller.js';
+
+describe('SsoController', () => {
+  afterEach(() => {
+    vi.unstubAllEnvs();
+  });
+
+  it('lists configured OIDC providers', () => {
+    vi.stubEnv('WORKOS_CLIENT_ID', 'workos-client');
+    vi.stubEnv('WORKOS_CLIENT_SECRET', 'workos-secret');
+    vi.stubEnv('WORKOS_ISSUER', 'https://auth.workos.com/sso/client_123');
+
+    const controller = new SsoController();
+    const providers = controller.list();
+
+    expect(providers.find((provider) => provider.id === 'workos')).toMatchObject({
+      configured: true,
+      loginMode: 'oidc',
+      callbackPath: '/api/auth/oauth2/callback/workos',
+      teamSync: { enabled: true, claim: 'organization_id' },
+    });
+  });
+
+  it('prefers SAML fallback for Keycloak when only the SAML login URL is configured', () => {
+    vi.stubEnv('KEYCLOAK_SAML_LOGIN_URL', 'https://sso.example.com/realms/mosaic/protocol/saml');
+
+    const controller = new SsoController();
+    const providers = controller.list();
+
+    expect(providers.find((provider) => provider.id === 'keycloak')).toMatchObject({
+      configured: true,
+      loginMode: 'saml',
+      samlFallback: {
+        configured: true,
+        loginUrl: 'https://sso.example.com/realms/mosaic/protocol/saml',
+      },
+    });
+  });
+});