resolveHeartbeatRunPrompt can no longer return prompt: null — the only
null producer (inferred commitments follow-ups) was deleted in
4b0151682e — so the two not-due short-circuits in
heartbeat-runner-execution.ts were dead branches. Narrow the resolution
type to string and delete both consumers.
HEARTBEAT_SKIP_LANES_BUSY had no remaining producer and
HeartbeatDeps.getCommandLaneSnapshots no prod reader (the per-lane busy
check was consolidated into requests-in-flight admission). Delete the
constant, the dep, and the tests that only exercised the dead seam;
retarget the retry-simulation tests at live retryable reasons and drop
the stale lanes-busy mention from the troubleshooting doc.
Peter Steinberger
717f77678a
