refactor(*): 平台架构 - 拆分后端领域模块并同步插件协议与模型能力

backend/internal/kernel/errors.go

@@ -0,0 +1,60 @@
+package kernel
+
+// AppError 是业务层对外公开的结构化错误。
+// Message 必须可安全展示给用户，Cause 仅用于保留内部诊断链路，不得直接写入 HTTP 响应。
+type AppError struct {
+	Status    int
+	Code      int
+	Reason    ErrorReason
+	Message   string
+	Retryable bool
+	Cause     error
+}
+
+func (e *AppError) Error() string {
+	if e == nil {
+		return ""
+	}
+	return e.Message
+}
+
+func (e *AppError) Unwrap() error {
+	if e == nil {
+		return nil
+	}
+	return e.Cause
+}
+
+func NewAppError(status int, message string) *AppError {
+	return &AppError{Status: status, Code: status, Reason: ReasonForStatus(status), Message: message}
+}
+
+func WrapAppError(status int, message string, cause error) *AppError {
+	err := NewAppError(status, message)
+	err.Cause = cause
+	return err
+}
+
+func RateLimited(message string) *AppError {
+	return &AppError{Status: CodeTooManyRequests, Code: CodeRateLimited, Reason: ReasonRateLimited, Message: message, Retryable: true}
+}
+
+func QuotaExceeded(message string) *AppError {
+	return &AppError{Status: CodeForbidden, Code: CodeQuotaExceeded, Reason: ReasonQuotaExceeded, Message: message}
+}
+
+func BadAuthRequest(message string) *AppError {
+	return NewAppError(400, message)
+}
+
+func NotFound(message string) *AppError {
+	return NewAppError(404, message)
+}
+
+func Unauthorized(message string) *AppError {
+	return NewAppError(401, message)
+}
+
+func Forbidden(message string) *AppError {
+	return NewAppError(403, message)
+}