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/core/exceptions.py

@@ -0,0 +1,89 @@
+"""统一异常定义"""
+from typing import Optional, Dict, Any
+from fastapi import HTTPException, status
+
+
+class BusinessError(HTTPException):
+    """业务异常基类"""
+
+    def __init__(
+        self,
+        message: str,
+        code: int = status.HTTP_400_BAD_REQUEST,
+        error_code: Optional[str] = None,
+        detail: Optional[Dict[str, Any]] = None,
+    ):
+        super().__init__(
+            status_code=code,
+            detail={
+                "message": message,
+                "error_code": error_code or f"ERR_{code}",
+                "detail": detail,
+            },
+        )
+        self.message = message
+        self.code = code
+        self.error_code = error_code
+
+
+class BadRequestError(BusinessError):
+    """400 错误请求"""
+
+    def __init__(self, message: str = "错误的请求", **kwargs):
+        super().__init__(message, status.HTTP_400_BAD_REQUEST, **kwargs)
+
+
+class UnauthorizedError(BusinessError):
+    """401 未授权"""
+
+    def __init__(self, message: str = "未授权", **kwargs):
+        super().__init__(message, status.HTTP_401_UNAUTHORIZED, **kwargs)
+
+
+class ForbiddenError(BusinessError):
+    """403 禁止访问"""
+
+    def __init__(self, message: str = "禁止访问", **kwargs):
+        super().__init__(message, status.HTTP_403_FORBIDDEN, **kwargs)
+
+
+class NotFoundError(BusinessError):
+    """404 未找到"""
+
+    def __init__(self, message: str = "资源未找到", **kwargs):
+        super().__init__(message, status.HTTP_404_NOT_FOUND, **kwargs)
+
+
+class ConflictError(BusinessError):
+    """409 冲突"""
+
+    def __init__(self, message: str = "资源冲突", **kwargs):
+        super().__init__(message, status.HTTP_409_CONFLICT, **kwargs)
+
+
+class ValidationError(BusinessError):
+    """422 验证错误"""
+
+    def __init__(self, message: str = "验证失败", **kwargs):
+        super().__init__(message, status.HTTP_422_UNPROCESSABLE_ENTITY, **kwargs)
+
+
+class InternalServerError(BusinessError):
+    """500 内部服务器错误"""
+
+    def __init__(self, message: str = "内部服务器错误", **kwargs):
+        super().__init__(message, status.HTTP_500_INTERNAL_SERVER_ERROR, **kwargs)
+
+
+class InsufficientPermissionsError(ForbiddenError):
+    """权限不足"""
+
+    def __init__(self, message: str = "权限不足", **kwargs):
+        super().__init__(message, error_code="INSUFFICIENT_PERMISSIONS", **kwargs)
+
+
+class ExternalServiceError(BusinessError):
+    """外部服务错误"""
+
+    def __init__(self, message: str = "外部服务异常", **kwargs):
+        super().__init__(message, status.HTTP_502_BAD_GATEWAY, error_code="EXTERNAL_SERVICE_ERROR", **kwargs)