fix(auth): Correct API paths and resolve build/type errors in tests and config

frontend/src/services/auth.ts

@@ -0,0 +1,47 @@
+import axios from "axios"
+
+const API_URL = import.meta.env.VITE_API_URL || ""
+
+export interface AuthResponse {
+  access_token: string
+  token_type: string
+}
+
+export interface UserResponse {
+  id: string
+  email: string
+}
+
+export const AuthService = {
+  async login(email: string, password: string): Promise<AuthResponse> {
+    const formData = new FormData()
+    formData.append("username", email) // OAuth2PasswordRequestForm uses 'username'
+    formData.append("password", password)
+
+    const response = await axios.post<AuthResponse>(`${API_URL}/auth/login`, formData)
+    if (response.data.access_token) {
+      localStorage.setItem("token", response.data.access_token)
+    }
+    return response.data
+  },
+
+  async register(email: string, password: string): Promise<UserResponse> {
+    const response = await axios.post<UserResponse>(`${API_URL}/auth/register`, {
+      email,
+      password,
+    })
+    return response.data
+  },
+
+  logout() {
+    localStorage.removeItem("token")
+  },
+
+  getToken() {
+    return localStorage.getItem("token")
+  },
+
+  isAuthenticated() {
+    return !!this.getToken()
+  },
+}