fix(ci): destroy stdout/stderr pipes after SIGKILL on timeout

Ubuntu CI symptom: even SIGKILL on the parent shell didn't unblock the
`close` event — the test stayed pending past vitest's 5s ceiling.

Root cause (most likely): dash on Ubuntu spawns `sleep` and when we kill
dash, sleep gets reparented to init but its stdout/stderr fds were
inherited from dash, keeping them alive from Node's POV. So Node's
child.stdout/stderr never get EOF, and `close` event on the (already
dead) dash never fires.

Fix: explicitly destroy() both pipes after sending SIGKILL. That forces
'close' to fire immediately regardless of orphaned child state.

Verified locally on macOS bash; pushing to test Ubuntu dash.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: oratis

packages/core/src/hooks/dispatcher.ts

@@ -123,8 +123,11 @@ export function runCommand(
     let killed = false;
     const timer = setTimeout(() => {
       killed = true;
-      // SIGKILL — see comment in bash.ts; dash on Ubuntu doesn't propagate SIGTERM.
+      // SIGKILL + destroy pipes — see bash.ts; needed for orphaned grandchild
+      // pipes on Ubuntu CI (dash doesn't propagate signals).
       child.kill('SIGKILL');
+      child.stdout?.destroy();
+      child.stderr?.destroy();
     }, opts.timeoutMs);
 
     child.stdout.on('data', (c: Buffer) => {

packages/core/src/tools/bash.ts

@@ -61,9 +61,12 @@ export const BashTool: ToolHandler = {
       let killed = false;
       const timer = setTimeout(() => {
         killed = true;
-        // SIGKILL (not SIGTERM) — on Ubuntu CI, dash doesn't propagate SIGTERM
-        // to its children fast enough, leaving `sleep` orphaned past test timeout.
+        // SIGKILL + destroy pipes — on Ubuntu CI, dash leaves orphaned children
+        // whose inherited stdout/stderr fds keep `close` from firing on the
+        // parent. Destroying the pipes forces close.
         child.kill('SIGKILL');
+        child.stdout?.destroy();
+        child.stderr?.destroy();
       }, timeoutMs);
 
       child.stdout.on('data', (chunk: Buffer) => {