feat: 初始化ERP平台底座项目结构

- 添加基础crate结构(erp-core, erp-common)
- 实现核心模块trait和事件总线
- 配置Docker开发环境(PostgreSQL+Redis)
- 添加Tauri桌面端基础框架
- 设置CI/CD工作流
- 编写项目协作规范文档(CLAUDE.md)

crates/erp-core/src/error.rs

@@ -0,0 +1,78 @@
+use axum::http::StatusCode;
+use axum::response::{IntoResponse, Response};
+use axum::Json;
+use serde::Serialize;
+
+/// 统一错误响应格式
+#[derive(Debug, Serialize)]
+pub struct ErrorResponse {
+    pub error: String,
+    pub message: String,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub details: Option<serde_json::Value>,
+}
+
+/// 平台级错误类型
+#[derive(Debug, thiserror::Error)]
+pub enum AppError {
+    #[error("资源未找到: {0}")]
+    NotFound(String),
+
+    #[error("验证失败: {0}")]
+    Validation(String),
+
+    #[error("未授权")]
+    Unauthorized,
+
+    #[error("禁止访问: {0}")]
+    Forbidden(String),
+
+    #[error("冲突: {0}")]
+    Conflict(String),
+
+    #[error("内部错误: {0}")]
+    Internal(String),
+}
+
+impl IntoResponse for AppError {
+    fn into_response(self) -> Response {
+        let (status, message) = match &self {
+            AppError::NotFound(_) => (StatusCode::NOT_FOUND, self.to_string()),
+            AppError::Validation(_) => (StatusCode::BAD_REQUEST, self.to_string()),
+            AppError::Unauthorized => (StatusCode::UNAUTHORIZED, "未授权".to_string()),
+            AppError::Forbidden(_) => (StatusCode::FORBIDDEN, self.to_string()),
+            AppError::Conflict(_) => (StatusCode::CONFLICT, self.to_string()),
+            AppError::Internal(_) => (StatusCode::INTERNAL_SERVER_ERROR, "内部错误".to_string()),
+        };
+
+        let body = ErrorResponse {
+            error: status.canonical_reason().unwrap_or("Error").to_string(),
+            message,
+            details: None,
+        };
+
+        (status, Json(body)).into_response()
+    }
+}
+
+impl From<anyhow::Error> for AppError {
+    fn from(err: anyhow::Error) -> Self {
+        AppError::Internal(err.to_string())
+    }
+}
+
+impl From<sea_orm::DbErr> for AppError {
+    fn from(err: sea_orm::DbErr) -> Self {
+        match err {
+            sea_orm::DbErr::RecordNotFound(msg) => AppError::NotFound(msg),
+            sea_orm::DbErr::Query(sea_orm::RuntimeErr::SqlxError(e))
+                if e.to_string().contains("duplicate key") =>
+            {
+                AppError::Conflict("记录已存在".to_string())
+            }
+            _ => AppError::Internal(err.to_string()),
+        }
+    }
+}
+
+pub type AppResult<T> = Result<T, AppError>;