🎉 Initial commit: QQuiz - 智能刷题与题库管理平台

## 功能特性

✅ **核心功能**
- 多文件上传与智能去重（基于 content_hash）
- 异步文档解析（支持 TXT/PDF/DOCX/XLSX）
- AI 智能题目提取与评分（OpenAI/Anthropic/Qwen）
- 断点续做与进度管理
- 自动错题本收集

✅ **技术栈**
- Backend: FastAPI + SQLAlchemy 2.0 + PostgreSQL
- Frontend: React 18 + Vite + Tailwind CSS
- Deployment: Docker Compose

✅ **项目结构**
- 53 个文件
- 完整的前后端分离架构
- Docker/源码双模部署支持

🚀 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

backend/main.py

@@ -0,0 +1,84 @@
+"""
+QQuiz FastAPI Application
+"""
+from fastapi import FastAPI
+from fastapi.middleware.cors import CORSMiddleware
+from contextlib import asynccontextmanager
+import os
+from dotenv import load_dotenv
+
+from database import init_db, init_default_config, get_db_context
+
+# Load environment variables
+load_dotenv()
+
+
+@asynccontextmanager
+async def lifespan(app: FastAPI):
+    """Application lifespan events"""
+    # Startup
+    print("🚀 Starting QQuiz Application...")
+
+    # Initialize database
+    await init_db()
+
+    # Initialize default configurations
+    async with get_db_context() as db:
+        await init_default_config(db)
+
+    # Create uploads directory
+    upload_dir = os.getenv("UPLOAD_DIR", "./uploads")
+    os.makedirs(upload_dir, exist_ok=True)
+    print(f"📁 Upload directory: {upload_dir}")
+
+    print("✅ Application started successfully!")
+
+    yield
+
+    # Shutdown
+    print("👋 Shutting down QQuiz Application...")
+
+
+# Create FastAPI app
+app = FastAPI(
+    title="QQuiz API",
+    description="智能刷题与题库管理平台",
+    version="1.0.0",
+    lifespan=lifespan
+)
+
+# Configure CORS
+cors_origins = os.getenv("CORS_ORIGINS", "http://localhost:3000").split(",")
+app.add_middleware(
+    CORSMiddleware,
+    allow_origins=cors_origins,
+    allow_credentials=True,
+    allow_methods=["*"],
+    allow_headers=["*"],
+)
+
+
+@app.get("/")
+async def root():
+    """Root endpoint"""
+    return {
+        "message": "Welcome to QQuiz API",
+        "version": "1.0.0",
+        "docs": "/docs"
+    }
+
+
+@app.get("/health")
+async def health_check():
+    """Health check endpoint"""
+    return {"status": "healthy"}
+
+
+# Import and include routers
+from routers import auth, exam, question, mistake, admin
+
+app.include_router(auth.router, prefix="/api/auth", tags=["Authentication"])
+app.include_router(exam.router, prefix="/api/exams", tags=["Exams"])
+app.include_router(question.router, prefix="/api/questions", tags=["Questions"])
+app.include_router(mistake.router, prefix="/api/mistakes", tags=["Mistakes"])
+app.include_router(admin.router, prefix="/api/admin", tags=["Admin"])