refactor(auth): use centralized config for API base URL

Replace inline SECUIRD_API constant definitions with imported config
module across all auth pages. This consolidates API URL configuration
into a single source of truth.

src/pages/auth/LoginPage.tsx

@@ -24,10 +24,7 @@ import {
 import { AddPasskeyWizard } from "@/components/security/AddPasskeyWizard";
 import { TotpEnrollmentWizard } from "@/components/security/TotpEnrollmentWizard";
 import { OAuthProvider } from "@/lib/oauth";
-
-type LoginStep = 'credentials' | 'totp' | 'webauthn' | 'passkey-email' | 'mfa-enrollment' | 'mfa';
-
-const SECUIRD_API = import.meta.env.VITE_API_BASE_URL ?? 'http://localhost:5000/api/v1';
+import { config } from "@/config";
 
 /**
  * Complete an OIDC authorization flow after the user has authenticated.
@@ -35,7 +32,7 @@ const SECUIRD_API = import.meta.env.VITE_API_BASE_URL ?? 'http://localhost:5000/
  * the auth code and returns the redirect URL for the calling application.
  */
 async function completeOidcFlow(oidcSessionId: string, token: string): Promise<string> {
-  const res = await fetch(`${SECUIRD_API}/oidc/complete`, {
+  const res = await fetch(`${config.api.baseUrl}/oidc/complete`, {
     method: 'POST',
     headers: { 'Content-Type': 'application/json' },
     body: JSON.stringify({ oidc_session_id: oidcSessionId, token }),