feat: implemented the frontier-based scheduling for the graph executor with simplified state management (gotta love .clone)

src/graph/script.rs

@@ -10,6 +10,7 @@ use std::time::Duration;
 use tokio::process::Command;
 use tokio::time::timeout;
 
+#[derive(Clone)]
 pub struct ScriptExecutor {
     base_dir: PathBuf,
 }