feat: Add JWT authentication to backend, configure frontend API client, fix streak layout

src/store/cbtStore.ts

@@ -1,3 +1,4 @@
+import { fetchWithAuth } from "@/lib/apiClient";
 import { create } from 'zustand'
 import { persist, StateStorage, createJSONStorage } from 'zustand/middleware'
 import { get, set, del } from 'idb-keyval'
@@ -252,7 +253,7 @@ export const useCBTStore = create<CBTState>()(
         if (!payload) return null;
 
         try {
-          const res = await fetch(`/api/attempts/submit`, {
+          const res = await fetchWithAuth(`/api/attempts/submit`, {
             method: 'POST',
             headers: { 'Content-Type': 'application/json' },
             body: JSON.stringify(payload),