Refinement passes run (one pass = every loader offered one rung).
Rungs committed across all loaders and passes.
Rungs whose payload came from the slice cache rather than a fetch.
True once the final geometry phase ran its ladders to completion.
Rungs deferred by the projected-density gate (a node already denser than its cap on screen; resumes when the camera moves in).
Progressive-refinement counters for the current load.