Add backlog tasks and launcher time helper tests

- Track follow-up cleanup work in Backlog.md
- Replace Date.now usage with shared nowMs helper
- Add launcher args/parser and core regression tests

launcher/main.test.ts

@@ -43,6 +43,7 @@ function runLauncher(argv: string[], env: NodeJS.ProcessEnv): RunResult {
     {
       env,
       encoding: 'utf8',
+      timeout: 10000,
     },
   );
   return {