v2.4.3

v2.4.3 — verify a genuinely separate mount, not a /home/* guess

Port of the x86 sibling's fix. Bug found by Bertrand Clech (renesenses)
against Tune OS's actual disk layout (single grown root partition, no
separate /home) — the source-path check was a /home/* string prefix, not
a mount-boundary test, so a pair would silently give a false sense of
protection on any host without a separate /home mount.

_ram_persist_add_pair now resolves the actual backing filesystem of both
the source and / (findmnt --target) and refuses, not just warns, when they
match.