feat: 初始化考培练系统项目

- 从服务器拉取完整代码
- 按框架规范整理项目结构
- 配置 Drone CI 测试环境部署
- 包含后端(FastAPI)、前端(Vue3)、管理端

技术栈: Vue3 + TypeScript + FastAPI + MySQL

backend/app/api/v1/course_chat.py

@@ -0,0 +1,190 @@
+"""
+与课程对话 API
+
+使用 Python 原生 AI 服务实现
+"""
+
+import json
+import logging
+from typing import Optional, Any
+
+from fastapi import APIRouter, HTTPException, Depends
+from fastapi.responses import StreamingResponse
+from pydantic import BaseModel, Field
+from sqlalchemy.ext.asyncio import AsyncSession
+
+from app.core.deps import get_db, get_current_user
+from app.models.user import User
+from app.services.ai.course_chat_service import course_chat_service_v2
+
+router = APIRouter()
+logger = logging.getLogger(__name__)
+
+
+class CourseChatRequest(BaseModel):
+    """课程对话请求"""
+    course_id: int = Field(..., description="课程ID")
+    query: str = Field(..., description="用户问题")
+    conversation_id: Optional[str] = Field(None, description="会话ID（续接对话时传入）")
+
+
+class ResponseModel(BaseModel):
+    """通用响应模型"""
+    code: int = 200
+    message: str = "success"
+    data: Optional[Any] = None
+
+
+async def _chat_with_course(
+    request: CourseChatRequest,
+    current_user: User,
+    db: AsyncSession
+):
+    """
+    Python 原生实现的流式对话
+    """
+    logger.info(
+        f"用户 {current_user.username} 与课程 {request.course_id} 对话: "
+        f"{request.query[:50]}..."
+    )
+    
+    async def generate_stream():
+        """生成 SSE 流"""
+        try:
+            async for event_type, data in course_chat_service_v2.chat_stream(
+                db=db,
+                course_id=request.course_id,
+                query=request.query,
+                user_id=current_user.id,
+                conversation_id=request.conversation_id
+            ):
+                if event_type == "conversation_started":
+                    yield f"data: {json.dumps({'event': 'conversation_started', 'conversation_id': data})}\n\n"
+                    logger.info(f"会话已创建: {data}")
+                
+                elif event_type == "chunk":
+                    yield f"data: {json.dumps({'event': 'message_chunk', 'chunk': data})}\n\n"
+                
+                elif event_type == "done":
+                    yield f"data: {json.dumps({'event': 'message_end', 'message': data})}\n\n"
+                    logger.info(f"对话完成，总长度: {len(data)}")
+                
+                elif event_type == "error":
+                    yield f"data: {json.dumps({'event': 'error', 'message': data})}\n\n"
+                    logger.error(f"对话错误: {data}")
+        
+        except Exception as e:
+            logger.error(f"流式对话异常: {e}", exc_info=True)
+            yield f"data: {json.dumps({'event': 'error', 'message': str(e)})}\n\n"
+    
+    return StreamingResponse(
+        generate_stream(),
+        media_type="text/event-stream",
+        headers={
+            "Cache-Control": "no-cache",
+            "Connection": "keep-alive",
+            "X-Accel-Buffering": "no"
+        }
+    )
+
+
+@router.post("/chat")
+async def chat_with_course(
+    request: CourseChatRequest,
+    current_user: User = Depends(get_current_user),
+    db: AsyncSession = Depends(get_db)
+):
+    """
+    与课程对话（流式响应）
+    
+    使用 Python 原生 AI 服务实现，支持多轮对话。
+    """
+    return await _chat_with_course(request, current_user, db)
+
+
+@router.get("/conversations")
+async def get_conversations(
+    course_id: Optional[int] = None,
+    limit: int = 20,
+    current_user: User = Depends(get_current_user),
+    db: AsyncSession = Depends(get_db)
+):
+    """
+    获取会话列表
+    
+    返回当前用户的历史会话列表
+    """
+    try:
+        conversations = await course_chat_service_v2.get_conversations(
+            user_id=current_user.id,
+            course_id=course_id,
+            limit=limit
+        )
+        
+        return ResponseModel(
+            code=200,
+            message="获取会话列表成功",
+            data={
+                "conversations": conversations,
+                "total": len(conversations)
+            }
+        )
+    
+    except Exception as e:
+        logger.error(f"获取会话列表失败: {e}", exc_info=True)
+        raise HTTPException(status_code=500, detail=f"获取会话列表失败: {str(e)}")
+
+
+@router.get("/messages")
+async def get_messages(
+    conversation_id: str,
+    limit: int = 50,
+    current_user: User = Depends(get_current_user),
+    db: AsyncSession = Depends(get_db)
+):
+    """
+    获取历史消息
+    
+    返回指定会话的历史消息
+    """
+    try:
+        messages = await course_chat_service_v2.get_messages(
+            conversation_id=conversation_id,
+            user_id=current_user.id,
+            limit=limit
+        )
+        
+        return ResponseModel(
+            code=200,
+            message="获取历史消息成功",
+            data={
+                "messages": messages,
+                "total": len(messages)
+            }
+        )
+    
+    except Exception as e:
+        logger.error(f"获取历史消息失败: {e}", exc_info=True)
+        raise HTTPException(status_code=500, detail=f"获取历史消息失败: {str(e)}")
+
+
+@router.get("/engines")
+async def list_chat_engines():
+    """
+    获取可用的对话引擎列表
+    """
+    return ResponseModel(
+        code=200,
+        message="获取对话引擎列表成功",
+        data={
+            "engines": [
+                {
+                    "id": "native",
+                    "name": "Python 原生实现",
+                    "description": "使用本地 AI 服务（4sapi.com + OpenRouter），支持流式输出和多轮对话",
+                    "default": True
+                }
+            ],
+            "default_engine": "native"
+        }
+    )