[ligon]

The intermittent replica-discovery test in issue 76 discarded its checkpoint failure reason. Retain that dictionary on the existing publication assertion, and add two deterministic tests showing that a fully caught-up replica still cannot bypass an expired backup or publication deadline. Both require the previous durable generation to remain acknowledged. Production code and timeout, placement, ownership and sealing rules are unchanged.

The historical failure was not reproduced and its original reason is unavailable. Issue 76 remains open for diagnosis; the injected deadline failures demonstrate the boundary behavior, not the historical cause.

Validation:

• Dedicated Slurm job 40654245: three focused repetitions passed; full suite at diagnostic commit 8cd3f31 had 2,480 passed, zero failures/errors/skips in 325.60 seconds.
• Dedicated job 40654291: final code/test pin 4f7a573 passed both added deadline cases and the existing shared-shutdown-deadline case (3 passed). Later changes are ledger-only. Receiving-node source/import receipts are retained.
• Independent source review found no blocking issue; reviewer did not run tests.

The ledger records commands, evidence locations, invariants and remaining questions: docs/replica-checkpoint-ledger.org. GitNexus query/impact/index refresh/change detection were attempted but its native library cannot load libssl.so.3; manual caller/diff review bounds the change to tests and the ledger. No installed CLI or coordinator state was changed.