feat: improve error handling and code quality

后端改进:
- 添加统一异常处理系统 (exceptions.py, response.py)
- 实现自定义异常类 (ValidationError, AuthorizationError, ResourceNotFoundError, BusinessLogicError)
- 配置全局异常处理器,统一 API 错误响应格式
- 迁移业务逻辑错误到自定义异常 (users.py, auth.py)
- 添加 SQL LIKE 通配符转义,防止通配符滥用
- 使用 EmailStr 进行邮箱格式验证
- 移除敏感字段暴露 (jwt_sub)

前端改进:
- 配置 ESLint 9 (flat config) 和 Prettier
- 修复所有 ESLint 错误和警告
- 移除未使用的变量和导入
- 为组件添加 PropTypes 默认值
- 统一代码格式和风格

backend/main.py

@@ -1,11 +1,16 @@
 from contextlib import asynccontextmanager
-from fastapi import FastAPI
+from fastapi import FastAPI, Request, status
 from fastapi.middleware.cors import CORSMiddleware
+from fastapi.responses import JSONResponse
+from fastapi.exceptions import RequestValidationError
+from pydantic import ValidationError as PydanticValidationError
 import logging
 from pathlib import Path
 
 from backend.config import settings
 from backend.models import init_db
+from backend.exceptions import BaseAPIException
+from backend.schemas.response import ErrorResponse, ErrorDetail
 
 # 配置日志
 settings.LOG_FILE.parent.mkdir(parents=True, exist_ok=True)
@@ -69,6 +74,59 @@ app.add_middleware(
 )
 
 
+# 全局异常处理器
+@app.exception_handler(BaseAPIException)
+async def api_exception_handler(request: Request, exc: BaseAPIException):
+    """处理自定义 API 异常"""
+    return JSONResponse(
+        status_code=exc.status_code,
+        content=ErrorResponse(
+            error=ErrorDetail(
+                code=exc.error_code,
+                message=exc.message
+            )
+        ).model_dump()
+    )
+
+
+@app.exception_handler(RequestValidationError)
+async def validation_exception_handler(request: Request, exc: RequestValidationError):
+    """处理请求验证错误"""
+    errors = exc.errors()
+    # 取第一个错误作为主要错误消息
+    first_error = errors[0] if errors else {}
+    field = ".".join(str(loc) for loc in first_error.get("loc", []))
+    message = first_error.get("msg", "验证错误")
+
+    return JSONResponse(
+        status_code=status.HTTP_422_UNPROCESSABLE_ENTITY,
+        content=ErrorResponse(
+            error=ErrorDetail(
+                code="VALIDATION_ERROR",
+                message=message,
+                field=field or None
+            )
+        ).model_dump()
+    )
+
+
+@app.exception_handler(Exception)
+async def general_exception_handler(request: Request, exc: Exception):
+    """处理未捕获的异常"""
+    logger.error(f"未处理的异常: {type(exc).__name__}: {str(exc)}", exc_info=True)
+
+    # 不向客户端暴露内部错误详情
+    return JSONResponse(
+        status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
+        content=ErrorResponse(
+            error=ErrorDetail(
+                code="INTERNAL_ERROR",
+                message="服务器内部错误，请稍后重试"
+            )
+        ).model_dump()
+    )
+
+
 # 健康检查端点
 @app.get("/health")
 async def health_check():