docs: clean up root markdown files and synchronize with v4.4.0 standards

- Relocate legacy implementation_plan.md to docs/contracts/nats-backplane/implementation_plan.md
- Synchronize root documentation (README, README.ko, BOOTSTRAP, BOOTSTRAP.ko, AGENTS, MESSAGING, IMPROVEMENTS) to latest v4.4.0 standards
- Consolidate IMPROVEMENTS.md to single source of truth (5 open / 31 completed tasks 1:1 matching section headers)
- Archive unanimous PASS review reports from Claude, Grok, Codex, and OpenCode along with Plan Rev.2

BOOTSTRAP.md

@@ -17,6 +17,10 @@ Before cloning this project into a new environment, you must first understand th
     *   `MULTI_AGENT_RULES.ko.md`: Definition of agent roles (PM, Worker, Reviewer) and event publication rules (Korean).
     *   `skills/`: A collection of shell scripts that execute multi-agent coordination and asynchronous job processing.
         *   `lib.sh`: The core orchestration shell functions and virtual environment (venv) auto-loading library.
+        *   `lib_py/`: Python core orchestration package.
+            *   `agents/`: Multi-agent CLI lifecycle adapters.
+            *   `delegation/`: Core asynchronous delegation engine and CAS state machine.
+            *   `loop/`: Autonomous planning-execution-review loop runtime.
         *   `multi-agent-mux-create/`: Script to launch isolated herdr agent sessions.
         *   `multi-agent-mux-stop/`: Script to gracefully stop agent sessions and update states.
         *   `multi-agent-mux-resume/`: Script to restore stopped agent sessions back to their previous conversation state.
@@ -24,14 +28,16 @@ Before cloning this project into a new environment, you must first understand th
         *   `multi-agent-mux-monitor/`: Monitor script to sync herdr states with the registry.
         *   `multi-agent-mux-delegate-job/`: Asynchronous job splitting and delegation module.
             *   `requirements.txt`: Python dependency list (`paho-mqtt`, `pyyaml`).
-            *   `scripts/`: Python scripts running the core business logic.
-                *   `registry.py`: Job registration, claiming, and atomic file lock control (CLI supported).
-                *   `job_subscriber.py`: Background event subscriber and audit log generator.
-                *   `publish_event.py`: Event publisher for runtime states and error traps.
-                *   `mqtt_common.py`: Common utility for connecting to the MQTT broker.
+            *   `scripts/`: Wire-compatibility shims for legacy callers.
+                *   `registry.py`: Job registration, claiming, and atomic file lock control shim.
+                *   `job_subscriber.py`: Background event subscriber and audit log generator shim.
+                *   `publish_event.py`: Event publisher for runtime states and error traps shim.
+                *   `mqtt_common.py`: Common utility for connecting to the MQTT broker shim.
         *   `multi-agent-mux-loop/`: Autonomous planning-execution-review loop orchestrator.
         *   `multi-agent-mux-orc-onboard/`: Orchestrator session UUID onboarding and sub-agent isolation helper.
+*   `AGENTS.md`: Behavioral guidelines and orchestrator scope guards.
 *   `MESSAGING.md`: Messaging scheme and wire protocol guidelines for MQTT communication between agents.
+*   `VERSIONS.md`: Release notes and 4-way lockstep version ledger.
 
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