🛡️ Claude Lane Stack v1.3.1 — Anti-join guard + detached heartbeats

Highlights

Hardening for v1.3.0 progressive accept.

lane-mode-check (anti join-wait)

Multi-task runs refuse MODE=full (exit 2 → STATUS: refused_full_on_multi_task). Implementers call it in preflight so parallel Agents cannot poll-until-done and reintroduce join-wait on the slowest task.

• OK: MODE=start / MODE=finish, or single-task MODE=full
• Emergency override (tests only): LANE_ALLOW_FULL=1

Detached heartbeats

lane-exec --heartbeat path now writes heartbeat.json on real activity (stdout/CPU, throttled). After MODE=start the Claude supervisor is gone — stall-check still sees liveness. Idle kill is unchanged (no timer-only heartbeat).

Tests

tests/test_progressive_accept.sh — mode-check refuse, accept task A while B runs, heartbeat write.

Upgrade

cd claude-lane-stack && git pull && git checkout v1.3.1
./install.sh
# fresh PM session
claude --agent dev-orchestrator

Full notes: CHANGELOG.md