rdmbair15m5 - changelog - feat-20260905-21-build-admission-control-and-fleet-deployment

Summary

Implemented and deployed FEAT-20260905-21: Build admission control across all six Mac fleet hosts. Enforces concurrent heavy build tree limits (hub rdmsm4x: 1, laptop Airs: 1, rdmpw3265m: 2, rdmpw3275m: 3) to eliminate host load starvation and prevent watchdog kernel panics. Built canonical build_slot.zsh engine supporting atomic acquire, queue contention reporting, dead process PID reaping, TTL expiration, and wrap command execution. Installed to ~/bin/build_slot.zsh on all six hosts and resolved ticket FEAT-20260905-21.

Scope & Attribution

• Hosts Touched: rdmsm4x, rdmbair15m5, rdmbair13m5, rdmpw3265m, rdmpw3275m, jdmbair13m5
• Agent Identity: agy@rdmbair15m5/1055213a
• Parent Ticket: EPIC-20260905-03
• Resolved Ticket: FEAT-20260905-21

Exact Files Touched

1. fleet/ops/build_slot.zsh: Canonical build admission control tool (commit 52cd9cc in fleet).
2. ~/bin/build_slot.zsh: Installed across all 6 hosts (rdmsm4x, rdmbair13m5, rdmbair15m5, rdmpw3265m, rdmpw3275m, jdmbair13m5).
3. ~/.agent-coordination/build-slots/<host>/: Atomic per-slot directory lock store.
4. issues/resolved/FEAT-20260905-21-...md: Ticket lifecycle transition to resolved (commit 7b6328b in issues).

Verification Evidence

1. build_slot.zsh acquire and build_slot.zsh list verified on rdmbair15m5 and rdmsm4x.
2. Contention & queue reporting verified: Attempting a second concurrent build while slot is held reports queue position and current holder without killing or dropping jobs.
3. Dead process reaping verified: Reaps slots whose owning PID exited or died via SIGKILL.
4. build_slot.zsh wrap verified: Correctly releases slots via EXIT trap after wrapped command completes.
5. All 6 hosts deployed and verified over SSH.
6. Git Remotes Synchronized: Commits pushed to fleet (git.ecs0.net) and backup (GitHub private remotes) across fleet and issues.