fix(lifecycle): use ProcessLifecycle for coordinated shutdown

Replace per-Watcher SIGINT handlers with a single ProcessLifecycle.install()
in TsWatch.start(). This eliminates competing signal handler races that left
orphaned child processes. Add @push.rocks/smartexit as direct dependency.

ts/tswatch.classes.watcher.ts

@@ -181,34 +181,13 @@ export class Watcher {
   }
 
   /**
-   * this method sets up a clean exit strategy
+   * Sets up timeout-based cleanup if configured.
+   * Signal handling (SIGINT/SIGTERM) is managed globally by ProcessLifecycle in TsWatch.
    */
   private async setupCleanup() {
-    // Last-resort synchronous cleanup — 'exit' event cannot await async work.
-    // By this point, SIGINT handler should have already called stop().
-    process.on('exit', () => {
-      if (this.currentExecution && !this.currentExecution.childProcess.killed) {
-        const pid = this.currentExecution.childProcess.pid;
-        if (pid) {
-          try {
-            process.kill(pid, 'SIGKILL');
-          } catch {
-            // Process may already be dead
-          }
-        }
-      }
-    });
-    process.on('SIGINT', async () => {
-      console.log('');
-      console.log('ok! got SIGINT We are exiting! Just cleaning up to exit neatly :)');
-      await this.stop();
-      process.exit(0);
-    });
-
-    // handle timeout
     if (this.options.timeout) {
       plugins.smartdelay.delayFor(this.options.timeout).then(async () => {
-        console.log(`timed out afer ${this.options.timeout} milliseconds! exiting!`);
+        console.log(`timed out after ${this.options.timeout} milliseconds! exiting!`);
         await this.stop();
         process.exit(0);
       });