fix(cli): recover stale rendezvous publication before declaring BUSY (#1760)

[umi008]

What does this PR do?

After CBM processes are hard-killed (pkill/kill -9), the runtime dir keeps the published socket/anchor/identity files while every file lock is kernel-released. The CLI activation guard probed generation and treated the ECONNREFUSED socket as an active daemon — a deliberate fail-closed choice that protects saturated BSD listeners — so install/update failed forever with "active CBM sessions ... could not be stopped safely" even though nothing was running. Only daemon-start paths ran the stale cleanup, which the CLI could never reach: deadlock by residue.

cli_activation_production_reserve now recognizes the provably-stale combination — generation present, lifetime reservation absent, startup lock already held — and runs the existing cbm_daemon_ipc_stale_generation_cleanup repair, then re-probes generation before deciding. The cleanup re-checks both conditions and refuses on a genuinely held reservation, so a live daemon (including a saturated BSD listener) is never disturbed and the guard falls back to the original BUSY verdict. POSIX-only; Windows keeps its rendezvous-record semantics unchanged.

Verified with an end-to-end regression test: a child listens and exits without unlink (hard-kill residue), then the real activation guard installs successfully, removes the residue, and records the completed phase.

Checklist

• Every commit is signed off (git commit -s) — required, CI rejects unsigned commits (DCO, see CONTRIBUTING.md)
• Tests pass locally (make -f Makefile.cbm test)
• Lint passes (make -f Makefile.cbm lint-ci)
• New behavior is covered by a test (reproduce-first for bug fixes)

[github-actions]

Thanks for opening this — it has been seen, and it is queued.

This note is automated, but it is not a brush-off: it exists so you know where your PR stands instead of having to guess from silence.

Current review status: working through a backlog. 0.9.1-rc.1 is out, so the release freeze that held reviews is over — but it left a large queue of open pull requests behind it, and we are reading through them oldest-first. The background is in discussion #1144.

What that means for this PR, concretely:

• It will not be closed for inactivity. No stale bot touches pull requests here.
• It may still sit a while before a human reads it. That is on us, not on you.
• Older PRs are read first, so a recent one is not being skipped — it is behind a queue.

Things that will genuinely speed it up whenever review does happen:

• Keep it rebased on main — the tree is moving quickly right now, and a conflicting branch cannot be reviewed as the diff you intended.
• Get CI green, or say which failures you believe are pre-existing.
• Keep the change to one claim. Bundled features and refactors get split before they get merged, which costs you a round trip.
• Every commit needs a sign-off (git commit -s) — CI enforces DCO.

If this fixes a bug, a reproduction we can run is worth more than a description of the symptom.

Thanks for contributing, and sorry in advance for the wait.