fix(backend): recursively kill yt-dlp child processes to prevent zombies

src-tauri/src/lib.rs

@@ -1505,6 +1505,7 @@ pub mod ipc;
 mod parity;
 mod platform;
 pub mod queue;
+pub mod process;
 pub mod retry;
 mod settings;
 pub use error::AppError;
@@ -2511,6 +2512,7 @@ pub(crate) async fn start_media_download_internal(
         let failure_reason = loop {
             tokio::select! {
                 _ = cancel_rx.changed() => {
+                    crate::process::kill_process_tree(child.pid());
                     let _ = child.kill();
                     if processing_started {
                         cleanup_media_processing_artifacts(&out_path).await;

src-tauri/src/process.rs

@@ -0,0 +1,26 @@
+use sysinfo::System;
+
+pub fn kill_process_tree(pid: u32) {
+    let mut sys = System::new();
+    sys.refresh_processes(sysinfo::ProcessesToUpdate::All, true);
+    
+    let mut to_kill = vec![sysinfo::Pid::from_u32(pid)];
+    let mut i = 0;
+    while i < to_kill.len() {
+        let current_pid = to_kill[i];
+        for (p, process) in sys.processes() {
+            if process.parent() == Some(current_pid) {
+                if !to_kill.contains(p) {
+                    to_kill.push(*p);
+                }
+            }
+        }
+        i += 1;
+    }
+    
+    for p in to_kill.into_iter().rev() {
+        if let Some(process) = sys.process(p) {
+            process.kill();
+        }
+    }
+}