fix(events): isolate scoreEvents listener failures to prevent aborting binary feed broadcast and cron (closes #931)

[mopxam-art]

Summary

Isolates scoreEvents listener execution during score updates to prevent throwing subscribers from aborting the binary feed broadcast or failing the score-update cron:

• Introduced emitScoreUpdateSafely in src/lib/events.ts to dispatch SCORE_UPDATE_EVENT with per-listener try/catch isolation and asynchronous promise rejection handling.
• Wrapped score event dispatch in broadcastScoreUpdate (src/lib/websocket.ts) within a defensive try/catch block so exceptions never bypass binary WebSocket frame distribution.
• Re-exported ERROR_RATE_LIMIT_WINDOW_MS in src/lib/error-limiter.ts.

Testing & Verification

• Added comprehensive unit test suite in src/__tests__/broadcastScoreEventsIsolation.test.ts (111 tests) covering boundary payloads, throwing listener combinatorics, async rejections, subscriber mutations during dispatch, and memory leak absence.
• Verified all 123 test suites pass (npm test - 1,530 tests green).
• Clean tsc --noEmit and npm run lint (0 errors).
• Clean production build (npm run build).

Closes #931