fix(issue-6): fail-closed registry timeout and TUI turn handshake

- Introduce finalize_unfinished in multi-agent-mux-delegate-job for fail-closed atomic transitions
- Enforce CAS dispatch_token and attempt_id pinning across engine, CLI, and lifecycle scripts
- Integrate Herdr wait_for_agent_idle turn handshake to prevent prompt loss and race conditions
- Resolve bash 3.2 set -u empty array expansion compatibility in lib.sh
- Preserve Issue #5 R2 contract in CAS transition engine (engine.py, publish_event.py, service.py)
- Add comprehensive regression suites (test_issue6_fail_closed.py, test_issue6_turn_handshake.py)
- Bump lockstep framework and skills to v4.4.1 across lib.sh, eager.py, VERSIONS.md, 8 SKILL.md
- Synchronize documentation (IMPROVEMENTS.md, MESSAGING.md, state-transitions.md, task.md, phase5-e2e.md)
- Unanimous PASS achieved across 4 reviewer team leaders (Claude, Codex, OpenCode, Grok)

Closes #6

BOOTSTRAP.md

@@ -2,7 +2,7 @@
 
 This document guides you through the setup and initialization procedures required to adopt the `herdr_agent_orchestration` orchestration and messaging backplane workflow in a new project, enabling a new developer or agent to get up and running quickly.
 
-[![Version: v4.4.0](https://img.shields.io/badge/version-v4.4.0-blue.svg)](VERSIONS.md)
+[![Version: v4.4.1](https://img.shields.io/badge/version-v4.4.1-blue.svg)](VERSIONS.md)
 
 A new agent can follow the steps in this guide sequentially to establish a stable and reliable initial environment.
 
@@ -202,4 +202,4 @@ rm -f ".mam/jobs/$JID.json" ".mam/jobs/$JID.lock"
 
 Once the setup is verified, onboarding agents (`claude`, `agy`, `hermes`, `grok`, `opencode`, `codex`) should immediately read the **[MULTI_AGENT_RULES.md](.agents/MULTI_AGENT_RULES.md)** guidelines in the .agents/ directory.
 
-The guidelines describe essential workflows—such as **surgical change constraints, cross-verification review loops, and pane snapshotting to prevent viewport truncation**—allowing new agents to quickly and safely integrate with the multi-agent workflow.
+The guidelines describe essential workflows—such as **surgical change constraints, cross-verification review loops, and pane snapshotting to prevent viewport truncation**—allowing new agents to quickly and safely integrate with the multi-agent workflow. In particular, once a delegated worker or reviewer finishes work and publishes the `completed` event, it must immediately end its turn without making any additional tool calls.