Source pattern verification tests:
- BUG-6: webhook calls wrapped in Promise.all (parallel, not sequential)
- BUG-7: SSE maps (spectatorCounts, fightReactions, ssePerIp) cleaned on disconnect
- BUG-4: no raw setTimeout in game code (all use trackedTimeout)
- BUG-F2: no silent .catch(() => {}) in frontend source
43 regression tests total, all passing.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>