Plugin created managers, hooks, intervals, and process listeners on
every load but had no teardown mechanism. On plugin reload, old
instances remained alive causing cumulative memory leaks.
- Add createPluginDispose() orchestrating shutdown sequence:
backgroundManager.shutdown() → skillMcpManager.disconnectAll() →
disposeHooks()
- Add disposeHooks() aggregator with safe optional chaining
- Wire dispose into index.ts to clean previous instance on reload
- Make dispose idempotent (safe to call multiple times)
Tests: 4 pass, 8 expects
YeonGyu-Kim