Retry a single failed loader without touching the orchestrator's
update lock. Returns true on success (failure cleared from the
registry — except for a lazy LOD level, where true means "retry
kicked" and the record is kept until the thunk settles), false on
continued failure (registry updated with new retry count), or false
if the path is no longer in failed-loaders. A registered lines path
waits for the session working-set gate before loading.
Retry a single failed loader without touching the orchestrator's update lock. Returns true on success (failure cleared from the registry — except for a lazy LOD level, where true means "retry kicked" and the record is kept until the thunk settles), false on continued failure (registry updated with new retry count), or false if the path is no longer in failed-loaders. A registered lines path waits for the session working-set gate before loading.