- Remove unused generationProfile parameter from verify runner
- Integrate PluginContractRegistry into petit-runner and stateful-runner
- Add deterministic hashStringToSeed to doctor (replaces Math.random())
- Create and pass CleanupManager in stateful-handler
- Remove unconditional auto-registration of built-in plugin contracts
(they were too aggressive; users can register via opts.pluginContracts)
- Build: clean | Tests: 849 pass, 0 fail