fix: attach module event dispatcher during startup

[localhost41]

Summary

Attach the module-event dispatcher as soon as the HRPC instance is created, before workletStart can construct a module and emit an event. The existing listener fan-out already drops events cleanly when an application has no subscriber, so eager attachment closes the startup race without changing subscription behavior.

The dispatcher remains idempotent per HRPC instance, and the subscription path still calls the same helper as a fallback.

Validation

• Added coverage that the dispatcher attaches once even without an application listener
• Added an ordering assertion that attachment happens before workletStart
• npm test -- --runInBand (481 tests)
• npm run typecheck
• npm run lint
• npm run build
• git diff --check

Closes #83