Fix flaky integration tests for channels and spaces functionality

[mattheworiordan]

The following integration tests are currently skipped due to flakiness:

1. channels.integration.test.ts: "should handle channel presence updates in realtime" - Flaky due to timing issues with presence synchronization
2. spaces.integration.test.ts: "should synchronize cursor positions across multiple clients" - Flaky due to race conditions in cursor updates

These tests need to be rewritten with better synchronization mechanisms and more robust error handling to prevent intermittent failures in CI.