feat: initial project setup for Meme Studio

Next.js 14 App Router application for managing homophone pun game levels:

- Better Auth with Prisma adapter for authentication
- MySQL database with Prisma ORM
- Level CRUD operations with drag-and-drop reordering
- Tencent COS integration for image uploads
- shadcn/ui components with Tailwind CSS
- TanStack Query for server state management

lib/auth-client.ts

@@ -0,0 +1,7 @@
+import { createAuthClient } from 'better-auth/react'
+
+export const authClient = createAuthClient({
+  baseURL: process.env.NEXT_PUBLIC_APP_URL || 'http://localhost:3000',
+})
+
+export const { signIn, signOut, useSession } = authClient