Delete internal/multiagent directory

internal/multiagent/execute_exit_error.go

@@ -1,15 +0,0 @@
-package multiagent
-
-import "fmt"
-
-// ExecuteExitError 表示 execute 命令非零退出（预期失败，非超时/中断/流异常）。
-type ExecuteExitError struct {
-	Code int
-}
-
-func (e *ExecuteExitError) Error() string {
-	if e == nil {
-		return "exit status unknown"
-	}
-	return fmt.Sprintf("exit status %d", e.Code)
-}