Refactor authentication and integration handling

- Exclude the 'MeView' endpoint from public API documentation, marking it as an internal authenticated endpoint.
- Enhance error handling in the 'IntegrationSettingsViewSet' to gracefully manage empty request data and improve logging for account and settings lookups.
- Update API key retrieval logic to ensure fallback mechanisms are more robust and informative.
- Refactor user data fetching in the auth store to utilize a unified API system, improving error handling and data consistency.

frontend/src/store/authStore.ts

@@ -4,6 +4,7 @@
  */
 import { create } from 'zustand';
 import { persist } from 'zustand/middleware';
+import { fetchAPI } from '../services/api';
 
 interface User {
   id: number;
@@ -192,27 +193,18 @@ export const useAuthStore = create<AuthState>()(
         }
         
         try {
-          const API_BASE_URL = import.meta.env.VITE_BACKEND_URL || 'https://api.igny8.com/api';
-          const token = state.token || getAuthToken();
-          
-          const response = await fetch(`${API_BASE_URL}/v1/auth/me/`, {
-            method: 'GET',
-            headers: {
-              'Content-Type': 'application/json',
-              ...(token ? { 'Authorization': `Bearer ${token}` } : {}),
-            },
-            credentials: 'include',
-          });
+          // Use unified API system - fetchAPI automatically handles auth token from store
+          const response = await fetchAPI('/v1/auth/me/');
 
-          const data = await response.json();
-
-          if (!response.ok || !data.success) {
-            throw new Error(data.message || 'Failed to refresh user data');
+          // fetchAPI extracts data from unified format {success: true, data: {user: {...}}}
+          // So response is {user: {...}}
+          if (!response || !response.user) {
+            throw new Error('Invalid user data received');
           }
 
           // Update user data with latest from server
           // This ensures account/plan changes are reflected immediately
-          set({ user: data.user });
+          set({ user: response.user });
         } catch (error: any) {
           // If refresh fails, don't logout - just log the error
           // User might still be authenticated, just couldn't refresh data