docs: 完善文档和清理项目，添加 Gemini 配置指南

主要更新：

📚 文档改进
- 新增 AI_CONFIGURATION.md：详细的 AI 提供商配置指南
- 新增 CHINA_MIRROR_GUIDE.md：中国镜像加速指南
- 删除 6 个过时文档（DEPLOYMENT.md, QUICK_START.md 等）
- 更新 README.md：添加 Gemini 功能特性和 AI 提供商对比表

🧹 脚本清理
- 删除 11 个重复/过时脚本（从 25 个减少到 14 个）
- 删除 PostgreSQL 相关脚本（项目使用 MySQL）
- 删除重复的启动脚本（start_windows.bat, start_app.bat 等）

⚙️ 配置文件更新
- 更新 .env.example：添加 Gemini 配置示例和说明
- 默认 AI_PROVIDER 改为 gemini（推荐）
- 添加各提供商的获取 API Key 链接

🎯 核心改进
- 突出 Gemini 原生 PDF 理解优势
- 提供清晰的 AI 提供商选择指南
- 简化项目结构，提高可维护性

清理内容：
- 删除 docs: DEPLOYMENT.md, DOCKER_MIRROR_SETUP.md, GITHUB_PUSH_GUIDE.md,
  QUICK_START.md, README_QUICKSTART.md, START_HERE.txt
- 删除 scripts: auto_setup_and_run.bat, check_postgres.bat, logs_windows.bat,
  push_to_github.bat, quick_config.bat, restart_docker.bat, setup_docker_mirror.bat,
  start_app.bat, start_postgres.bat, start_windows.bat, start_windows_china.bat

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

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

backend/Dockerfile

@@ -2,10 +2,9 @@ FROM python:3.11-slim
 
 WORKDIR /app
 
-# Install system dependencies
-RUN apt-get update && apt-get install -y \
+# Install system dependencies (gcc for compiling Python packages)
+RUN apt-get update && apt-get install -y --no-install-recommends \
     gcc \
-    postgresql-client \
     && rm -rf /var/lib/apt/lists/*
 
 # Copy requirements and install Python dependencies

backend/Dockerfile.china

@@ -0,0 +1,32 @@
+# Dockerfile with China mirrors for faster builds
+# Usage: docker build -f Dockerfile.china -t qquiz-backend .
+
+FROM python:3.11-slim
+
+WORKDIR /app
+
+# Use Alibaba Cloud mirror for faster apt-get
+RUN sed -i 's/deb.debian.org/mirrors.aliyun.com/g' /etc/apt/sources.list.d/debian.sources 2>/dev/null || \
+    sed -i 's/deb.debian.org/mirrors.aliyun.com/g' /etc/apt/sources.list || true
+
+# Install system dependencies (gcc for compiling Python packages)
+RUN apt-get update && apt-get install -y --no-install-recommends \
+    gcc \
+    && rm -rf /var/lib/apt/lists/*
+
+# Copy requirements and install Python dependencies
+COPY requirements.txt .
+# Use Tsinghua PyPI mirror for faster pip install
+RUN pip install --no-cache-dir -i https://pypi.tuna.tsinghua.edu.cn/simple -r requirements.txt
+
+# Copy application code
+COPY . .
+
+# Create uploads directory
+RUN mkdir -p uploads
+
+# Expose port
+EXPOSE 8000
+
+# Run database migrations and start server
+CMD alembic upgrade head && uvicorn main:app --host 0.0.0.0 --port 8000

backend/services/auth_service.py

@@ -28,24 +28,19 @@ async def get_current_user(
         headers={"WWW-Authenticate": "Bearer"},
     )
 
-    print(f"🔍 Received token (first 50 chars): {token[:50] if token else 'None'}...")
-
     # Decode token
     payload = decode_access_token(token)
     if payload is None:
-        print(f"❌ Token decode failed - Invalid or expired token")
         raise credentials_exception
 
     user_id = payload.get("sub")
     if user_id is None:
-        print(f"❌ No 'sub' in payload: {payload}")
         raise credentials_exception
 
     # Convert user_id to int if it's a string
     try:
         user_id = int(user_id)
     except (ValueError, TypeError):
-        print(f"❌ Invalid user_id format: {user_id}")
         raise credentials_exception
 
     # Get user from database
@@ -53,10 +48,8 @@ async def get_current_user(
     user = result.scalar_one_or_none()
 
     if user is None:
-        print(f"❌ User not found with id: {user_id}")
         raise credentials_exception
 
-    print(f"✅ User authenticated: {user.username} (id={user.id})")
     return user
 
 

backend/utils.py

@@ -37,8 +37,6 @@ def create_access_token(data: dict, expires_delta: Optional[timedelta] = None) -
         expire = datetime.utcnow() + timedelta(minutes=ACCESS_TOKEN_EXPIRE_MINUTES)
 
     to_encode.update({"exp": expire})
-    print(f"🔑 Creating token with SECRET_KEY (first 20 chars): {SECRET_KEY[:20]}...")
-    print(f"📦 Token payload: {to_encode}")
     encoded_jwt = jwt.encode(to_encode, SECRET_KEY, algorithm=ALGORITHM)
     return encoded_jwt
 
@@ -46,12 +44,9 @@ def create_access_token(data: dict, expires_delta: Optional[timedelta] = None) -
 def decode_access_token(token: str) -> Optional[dict]:
     """Decode a JWT access token"""
     try:
-        print(f"🔑 SECRET_KEY (first 20 chars): {SECRET_KEY[:20]}...")
         payload = jwt.decode(token, SECRET_KEY, algorithms=[ALGORITHM])
-        print(f"✅ Token decoded successfully: {payload}")
         return payload
-    except JWTError as e:
-        print(f"❌ JWT decode error: {type(e).__name__}: {str(e)}")
+    except JWTError:
         return None