feat: implement Account page and ThemeProvider; refactor App component and sidebar navigation

src/services/auth.ts

@@ -1,3 +1,12 @@
+interface Plan {
+  id: number
+  code: string
+  name: string
+  description: string
+  credits: number
+  max_credits: number
+}
+
 interface User {
   id: string
   email: string
@@ -9,6 +18,8 @@ interface User {
   providers: string[]
   api_token?: string
   api_token_expires_at?: string | null
+  plan?: Plan
+  credits?: number
 }
 
 interface AuthResponse {
@@ -125,4 +136,4 @@ class AuthService {
 }
 
 export const authService = new AuthService()
-export type { User }
+export type { User, Plan }