fix(watcher): always tree-kill on stop regardless of childProcess.killed flag

The direct bash child may already be dead from terminal SIGINT while
grandchildren (tsrun, devserver) are still running. Removing the .killed
guard ensures tree-kill always runs to clean up the entire process tree.

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@git.zone/tswatch",
-  "version": "3.2.2",
+  "version": "3.2.3",
   "private": false,
   "description": "A development tool for automatically watching and re-compiling TypeScript projects upon detecting file changes, enhancing developer workflows.",
   "exports": {