Expose RECORDING_ENCODING_* settings to override the default LiveKit
Egress preset (H264_720P_30). When RECORDING_ENCODING_ENABLED is True,
the provided width/height/framerate/bitrate/keyframe values are passed
as advanced EncodingOptions. Lowering framerate and bitrate reduces
recording file size and egress worker CPU load.
Disabled by default, preserving current behaviour.
Add comprehensive recording documentation explaining system requirements
and component interactions to help administrators understand infrastructure
needs and troubleshoot recording functionality.