fix: ensure shell cmds can be properly aborted (#2339)

packages/opencode/src/session/index.ts

@@ -1141,6 +1141,7 @@ export namespace Session {
     const proc = spawn(shell, args, {
       cwd: app.path.cwd,
       signal: abort.signal,
+      detached: true,
       stdio: ["ignore", "pipe", "pipe"],
       env: {
         ...process.env,
@@ -1148,6 +1149,11 @@ export namespace Session {
       },
     })
 
+    abort.signal.addEventListener("abort", () => {
+      if (!proc.pid) return
+      process.kill(-proc.pid)
+    })
+
     let output = ""
 
     proc.stdout?.on("data", (chunk) => {