fix: add /mobile prefix to all client-side fetch() calls for basePath

src/app/upgrade/page.tsx

@@ -112,7 +112,7 @@ function UpgradeContent() {
       window.history.replaceState({}, "", newUrl);
       // Refresh user data
       if (token) {
-        fetch("/api/auth/me", {
+        fetch("/mobile/api/auth/me", {
           headers: { Authorization: `Bearer ${token}` },
         })
           .then((r) => r.json())
@@ -142,7 +142,7 @@ function UpgradeContent() {
     setMessage(null);
 
     try {
-      const res = await fetch("/api/upgrade/create-checkout", {
+      const res = await fetch("/mobile/api/upgrade/create-checkout", {
         method: "POST",
         headers: {
           "Content-Type": "application/json",