Add option to prevent 24/7 recording when alwaysAvailable is enabled #5587
Description
Describe the feature
When the alwaysAvailable flag is enabled, MediaMTX begins recording 24/7 even if no source is currently connected to the path. This leads to continuous creation of empty or useless recordings.
It would be very helpful to have an additional option—something like recordOnConnect—that ensures recording only starts when an actual source connects (i.e., when the path becomes active due to an incoming stream, not simply because it is marked as always available).
This would allow users to keep paths pre-initialized with alwaysAvailable while avoiding unnecessary recordings when no stream is present.