fix(events): settle WebSocket waiters when listeners throw (#2491)

## Summary

- Continue delivering each event when an earlier callback throws, so
detached one-time listeners and `emitted()` waiters settle and clean up
their companions.
- Rethrow the exact first callback failure, including `undefined`,
`false`, and `Error`, after all same-event listeners have run.
- Cover six stable/beta Realtime and Responses WebSocket transports,
current server errors versus subsequent `PRIVATE_FUTURE_EVENT` payloads,
terminal close, reentrant snapshots, and linear-time dispatch.

## Validation

- Node 22.23 and Node 26.7: 6,866 handwritten tests and 556 generated
tests on each runtime.
- 20 regression failures on baseline; 98 focused and existing emitter
tests pass with the fix.
- Canonical lint, strict typing, build, published TypeScript 4.9 and 6,
publint, ATTW (`Types ok!`), and packed-installed CommonJS/ESM checks.