14 cases: RELEASE validation (valid/invalid/missing), tag consistency,
status on empty state, fault-injected refusal with no pointer + single
valid refusal log line, healthy activation, pointer fields, repeat
activation append-only log, rollback-without-previous refusal.
Harness fix learned the hard way: restore RELEASE from backup inline
after the missing-file case (mv-back restored the mutated file); single
exit trap self-heals the repo state.
Closes#12
