feat(data-streams): make the open stream limit a room option
Rename MAX_OPEN_STREAMS_PER_PARTICIPANT to DEFAULT_MAX_OPEN_STREAMS_PER_PARTICIPANT and allow overriding it with dataStream.maxOpenStreamsPerParticipant, alongside maxPayloadByteLength.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>