feat(registry): add promise lifecycle API

[ricardo-devis-agullo]

Summary

• return promises from registry.start(), registry.close(), and registry.register() while preserving callback overloads
• normalize startup failures to Error and emit a one-time callback deprecation warning
• cover promise resolution/rejection, callback compatibility, mixed usage, and graceful shutdown timing

Testing

• npm run build && npm test in packages/oc (969 passing)
• root npm test was attempted but is blocked by an existing Turbo race where metadata adapter tests cannot resolve oc-metadata-adapters-utils; the affected oc package passes independently

Closes #1528