feat(frontend): Refactor to cookie-based auth and add /api/v1 prefix

frontend/src/services/api.ts

@@ -0,0 +1,10 @@
+import axios from "axios"
+
+const API_URL = import.meta.env.VITE_API_URL || ""
+
+const api = axios.create({
+  baseURL: `${API_URL}/api/v1`,
+  withCredentials: true, // Crucial for HttpOnly cookies
+})
+
+export default api