Problem:
Erigon can't remove old (frozen) files. Not blocks files, not state files.
It's problem for --prune.mode=minimal with big uptime - it only creating-merging files but never delete old history files.

Idea:
mdbx has FreeList logic - whithout any per-page atomics
if we implement same logic for "old files - free list" - then we will not need refcnt atomics

Related:

• state, prune: locally delete old commitment history snapshot files #21199