BREAKING CHANGE(lifecycle): redesign SmartExit with ProcessLifecycle singleton

SmartExit constructor no longer installs signal handlers.
Applications must call ProcessLifecycle.install() explicitly.
Split into SmartExit (instance process tracking) and ProcessLifecycle (global signal coordination).
Remove @push.rocks/smartdelay dependency.

package.json

@@ -20,7 +20,6 @@
   },
   "dependencies": {
     "@push.rocks/lik": "^6.2.2",
-    "@push.rocks/smartdelay": "^3.0.5",
     "@push.rocks/smartpromise": "^4.2.3",
     "tree-kill": "^1.2.2"
   },