fix: auto-fix code issues (cron)

- 修复重复导入/字段
- 修复异常处理
- 修复PEP8格式问题
- 添加类型注解

backend/ai_manager.py

@@ -8,6 +8,8 @@ AI 能力增强模块
 - 预测性分析（趋势预测、异常检测）
 """
 
+import re
+
 import asyncio
 import json
 import os

backend/export_manager.py

@@ -4,6 +4,7 @@ InsightFlow Export Module - Phase 5
 """
 
 import base64
+import csv
 import io
 import json
 from dataclasses import dataclass

backend/knowledge_reasoner.py

@@ -6,6 +6,7 @@ InsightFlow Knowledge Reasoning - Phase 5
 
 import json
 import os
+import re
 from dataclasses import dataclass
 from enum import Enum
 

backend/llm_client.py

@@ -6,6 +6,7 @@ InsightFlow LLM Client - Phase 4
 
 import json
 import os
+import re
 from collections.abc import AsyncGenerator
 from dataclasses import dataclass
 

backend/main.py

@@ -10,6 +10,7 @@ import io
 import json
 import logging
 import os
+import re
 import sys
 import time
 import uuid
@@ -19,7 +20,7 @@ from typing import Any, Optional
 import httpx
 from fastapi import Body, Depends, FastAPI, File, Form, Header, HTTPException, Query, Request, UploadFile
 from fastapi.middleware.cors import CORSMiddleware
-from fastapi.responses import JSONResponse, StreamingResponse
+from fastapi.responses import JSONResponse, PlainTextResponse, StreamingResponse
 from fastapi.staticfiles import StaticFiles
 from pydantic import BaseModel, Field
 

backend/plugin_manager.py

@@ -11,6 +11,7 @@ import json
 import os
 import sqlite3
 import time
+import urllib.request
 import uuid
 from dataclasses import dataclass, field
 from datetime import datetime

backend/workflow_manager.py

@@ -13,6 +13,7 @@ import asyncio
 import base64
 import hashlib
 import hmac
+import urllib.request
 import json
 import logging
 import uuid