release(v4.9.3): u1e no longer writes the checkout's .mam/shim/herdr - archive the review reports and bump the lockstep version

Review loop (--review-only, --all-reviewer): round 1 (@3a30d7d) 4/4 PASS;
each reviewer reproduced W1 failing on the pre-fix tree. Seven #50/#55 and
leak modules (112 tests) from a clean worktree left no .mam in the
checkout.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01VCgu9Fa9iT7TbJUSzdq4Ff

.agents/skills/multi-agent-mux-stop/SKILL.md

@@ -1,7 +1,7 @@
 ---
 name: multi-agent-mux-stop
 description: "Stop an agent herdr session (claude, antigravity/agy) and update .mam/agent-sessions.yaml. Default stops gracefully and marks status=stopped with conversation preserved for resume. Does NOT delete on-disk conversation artifacts (jsonl/db) — those are preserved unless --purge-conversation is passed. Use when ending a work session, switching to a different one, or cleaning up before a fresh start."
-version: 4.9.2
+version: 4.9.3
 author: godopu
 license: MIT
 platforms: [linux, macos]