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

CLAUDE.md

@@ -0,0 +1,75 @@
+# CLAUDE.md
+
+This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.
+
+## Project Overview
+
+Meme Studio is a homophone pun game operation platform built with Next.js 14 (App Router). It provides level configuration management for a wordplay game.
+
+## Commands
+
+```bash
+npm run dev          # Start development server
+npm run build        # Production build
+npm run lint         # Run ESLint
+
+# Database (Prisma + MySQL)
+npm run db:generate  # Generate Prisma client
+npm run db:push      # Push schema changes (dev)
+npm run db:migrate   # Create migration
+npm run db:studio    # Open Prisma Studio
+npm run db:seed      # Create/update admin user
+```
+
+## Architecture
+
+### Tech Stack
+- **Framework**: Next.js 14 App Router
+- **Auth**: Better Auth with Prisma adapter (email/password)
+- **Database**: MySQL via Prisma ORM
+- **UI**: shadcn/ui + Tailwind CSS
+- **State**: TanStack Query for server state
+- **Drag & Drop**: @dnd-kit/sortable
+
+### Key Patterns
+
+**Route Groups**:
+- `app/(auth)/` - Login page (no sidebar)
+- `app/(dashboard)/` - Protected pages with sidebar layout
+
+**Auth Flow**:
+- `lib/auth.ts` - Server-side Better Auth config
+- `lib/auth-client.ts` - Client-side auth hooks (`useSession`, `signIn`, `signOut`)
+- `middleware.ts` - Cookie-based session check (cannot use Prisma in Edge Runtime)
+
+**API Routes**:
+- `/api/auth/[...all]` - Better Auth endpoints
+- `/api/levels` - CRUD for game levels
+- `/api/levels/reorder` - Batch update sort order
+- `/api/cos/temp-key` - Tencent COS temporary credentials
+
+**Database Models**:
+- `Level` - Game levels with image, answer, hints, sortOrder
+- `User`, `Session`, `Account`, `Verification` - Better Auth models
+
+### Environment Variables
+
+Required in `.env`:
+```
+DATABASE_URL=mysql://...
+BETTER_AUTH_SECRET=     # 32+ chars, generate with: openssl rand -base64 32
+BETTER_AUTH_URL=http://localhost:3000
+ADMIN_EMAIL=
+ADMIN_PASSWORD=
+COS_SECRET_ID=          # Tencent Cloud COS
+COS_SECRET_KEY=
+COS_BUCKET=
+COS_REGION=
+COS_APPID=
+```
+
+## Important Notes
+
+- Middleware uses cookie check only (Prisma doesn't work in Edge Runtime)
+- Password hashing must use `hashPassword` from `better-auth/crypto` for compatibility
+- Session model requires `token` field with unique constraint