Refactor API structure and integrate new modular API client

- Replaced legacy apiService with a new modular api client structure.
- Updated AuthContext, OAuthButtons, and AuthCallbackPage to use the new api client.
- Created separate services for auth, sounds, playlists, and users.
- Implemented centralized API configuration and error handling.
- Added support for OAuth providers and token exchange.
- Introduced a Toaster component for notifications in App.
- Updated API endpoints and request handling for better maintainability.

src/contexts/AuthContext.tsx

@@ -1,5 +1,5 @@
 import { createContext, useContext, useEffect, useState, type ReactNode } from 'react'
-import { apiService } from '@/lib/api'
+import { api } from '@/lib/api'
 import type { AuthContextType, User, LoginRequest, RegisterRequest } from '@/types/auth'
 
 const AuthContext = createContext<AuthContextType | null>(null)
@@ -24,7 +24,7 @@ export function AuthProvider({ children }: AuthProviderProps) {
     const initAuth = async () => {
       try {
         // Try to get user info using cookies
-        const user = await apiService.getMe()
+        const user = await api.auth.getMe()
         setUser(user)
       } catch {
         // User is not authenticated - this is normal for logged out users
@@ -37,8 +37,8 @@ export function AuthProvider({ children }: AuthProviderProps) {
 
   const login = async (credentials: LoginRequest) => {
     try {
-      const response = await apiService.login(credentials)
-      setUser(response.user)
+      const user = await api.auth.login(credentials)
+      setUser(user)
     } catch (error) {
       console.error('Login failed:', error)
       throw error
@@ -47,8 +47,8 @@ export function AuthProvider({ children }: AuthProviderProps) {
 
   const register = async (data: RegisterRequest) => {
     try {
-      const response = await apiService.register(data)
-      setUser(response.user)
+      const user = await api.auth.register(data)
+      setUser(user)
     } catch (error) {
       console.error('Registration failed:', error)
       throw error
@@ -56,7 +56,7 @@ export function AuthProvider({ children }: AuthProviderProps) {
   }
 
   const logout = async () => {
-    await apiService.logout()
+    await api.auth.logout()
     setUser(null)
   }