fix(desktop): shut down cleanly with workspace terminals (#3268)

Workspace terminal shutdown only signaled an npm wrapper, leaving Electron alive with broken output pipes. Make the signal-handling runner the terminal-owned process and route external Electron termination through the existing quit lifecycle.

packages/desktop/scripts/dev-runner-config.test.mjs

@@ -1,7 +1,23 @@
 import { describe, expect, test } from "vitest";
-import { createElectronSpawnOptions, resolveChildKillTarget } from "./dev-runner-config.mjs";
+import { readFileSync } from "node:fs";
+import {
+  createElectronSpawnOptions,
+  registerDevRunnerShutdownSignals,
+  resolveChildKillTarget,
+} from "./dev-runner-config.mjs";
 
 describe("desktop dev process ownership", () => {
+  test("makes the signal-handling runner the workspace terminal process", () => {
+    const paseoConfig = JSON.parse(
+      readFileSync(new URL("../../../paseo.json", import.meta.url), "utf8"),
+    );
+    const devScript = readFileSync(new URL("./dev.sh", import.meta.url), "utf8");
+
+    expect(paseoConfig.scripts.desktop.command).toContain("exec ./packages/desktop/scripts/dev.sh");
+    expect(devScript).toContain('npm --prefix "$DESKTOP_DIR" run build:main');
+    expect(devScript).toContain('exec node "$SCRIPT_DIR/dev-runner.mjs"');
+  });
+
   test("keeps Electron in the runner process group", () => {
     const options = createElectronSpawnOptions({
       env: { PATH: "/usr/bin" },
@@ -23,4 +39,24 @@ describe("desktop dev process ownership", () => {
     expect(resolveChildKillTarget(42, true)).toBe(-42);
     expect(resolveChildKillTarget(42, false)).toBe(42);
   });
+
+  test("stops children when the owning terminal hangs up", () => {
+    const listeners = new Map();
+    const receivedSignals = [];
+
+    registerDevRunnerShutdownSignals({
+      signalSource: {
+        on(signal, listener) {
+          listeners.set(signal, listener);
+        },
+      },
+      stop(signal) {
+        receivedSignals.push(signal);
+      },
+    });
+
+    expect(Array.from(listeners.keys())).toEqual(["SIGHUP", "SIGINT", "SIGTERM"]);
+    listeners.get("SIGHUP")();
+    expect(receivedSignals).toEqual(["SIGTERM"]);
+  });
 });