feat(core): Add cwd option and child-process execution for custom working directory; implement signal-forwarding child runner; update docs and bump package version to 1.4.0

ts/00_commitinfo_data.ts

@@ -3,6 +3,6 @@
  */
 export const commitinfo = {
   name: '@git.zone/tsrun',
-  version: '1.3.4',
+  version: '1.5.0',
   description: 'run typescript programs efficiently'
 }