fix(03): login redirect + API internal URL for Docker networking

- Use window.location.href for full page reload after login (ensures auth state)
- Add API_INTERNAL_URL for server-side requests within Docker network
- Remove unnecessary credentials:'include' from SSR fetch calls
- Update planning state for Phase 03 progress

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

apps/web/src/app/(auth)/login/page.tsx

@@ -27,8 +27,7 @@ export default function LoginPage() {
     startTransition(async () => {
       const result = await login(formData);
       if (result.success) {
-        router.push('/');
-        router.refresh();
+        window.location.href = '/';
       } else {
         setError(result.error ?? 'invalidCredentials');
       }