Add centralized API client with axios interceptors, remove vue-axios

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

src/api/auth.js

@@ -0,0 +1,33 @@
+import axios from 'axios';
+import { getCookie, setCookie, setCookieWithoutExpiration } from '@/utils/cookieUtil.js';
+
+/**
+ * Refresh the access token using the refresh token cookie.
+ * Uses plain axios (not apiClient) to avoid interceptor loops.
+ * @returns {Promise<string>} The new access token.
+ */
+export async function refreshTokenAndGetNew() {
+  const api = '/api/oauth/token';
+  const config = {
+    headers: {
+      'Content-Type': 'application/x-www-form-urlencoded',
+    },
+  };
+  const data = {
+    grant_type: 'refresh_token',
+    refresh_token: getCookie('luciaRefreshToken'),
+  };
+
+  const response = await axios.post(api, data, config);
+  const newAccessToken = response.data.access_token;
+  const newRefreshToken = response.data.refresh_token;
+
+  setCookieWithoutExpiration('luciaToken', newAccessToken);
+  // Expire in ~6 months
+  const expiredMs = new Date();
+  expiredMs.setMonth(expiredMs.getMonth() + 6);
+  const days = Math.ceil((expiredMs.getTime() - Date.now()) / (24 * 60 * 60 * 1000));
+  setCookie('luciaRefreshToken', newRefreshToken, days);
+
+  return newAccessToken;
+}