refactor: implement automatic token refresh and credential support for auth API client

frontend/src/api/apiClient.ts

@@ -1,10 +1,30 @@
 import axios from "axios";
 
-const apiClient = axios.create({
+const authApiClient = axios.create({
   baseURL: `${import.meta.env.VITE_API_URL}/api/auth/`,
+  withCredentials: true,
   headers: {
     "Content-Type": "application/json",
   },
 });
 
-export default apiClient;
+authApiClient.interceptors.response.use(
+  (response) => response,
+  async (error) => {
+    if (error.response.status === 401) {
+      // token expired, refresh it
+      try {
+        const response = await authApiClient.post("refresh/");
+        if (response.status === 200) {
+          // refresh successful, retry the request
+          return authApiClient(error.config);
+        }
+      } catch (error) {
+        return Promise.reject(error);
+      }
+    }
+    return Promise.reject(error);
+  },
+);
+
+export default authApiClient;

frontend/src/pages/Activate.tsx

@@ -1,7 +1,7 @@
 import { CheckCircleIcon, XCircleIcon } from "@phosphor-icons/react";
 import { useEffect, useRef, useState } from "react";
 import { useNavigate, useParams } from "react-router-dom";
-import apiClient from "../api/apiClient";
+import authApiClient from "../api/apiClient";
 import Logo from "../components/Logo";
 
 export default function Activate() {
@@ -20,7 +20,7 @@ export default function Activate() {
 
     const activateAccount = async () => {
       try {
-        await apiClient.get(`/activate/${uidb64}/${token}/`);
+        await authApiClient.get(`/activate/${uidb64}/${token}/`);
         setStatus("success");
       } catch (err) {
         console.error("Activation error:", err);

frontend/src/pages/Register.tsx

@@ -5,7 +5,7 @@ import { useState } from "react";
 import { useForm } from "react-hook-form";
 import { useNavigate } from "react-router-dom";
 import { z } from "zod";
-import apiClient from "../api/apiClient";
+import authApiClient from "../api/apiClient";
 import Logo from "../components/Logo";
 import FormField from "../components/ui/FormField";
 
@@ -41,7 +41,7 @@ export default function Register() {
     setIsLoading(true);
     setApiError(null);
     try {
-      await apiClient.post("/register/", {
+      await authApiClient.post("/register/", {
         full_name: data.full_name,
         email: data.email,
         password: data.password,