release(v4.8.9): tests no longer take the checkout's loop lock - archive the review reports and bump the lockstep version

Merge-workspace review loop (--all-reviewer): round 1 (@a93c9bf) 4/4
PASS. Full suite at a93c9bf on macOS / Python 3.9 / herdr 0.9.3 with
WORKSPACE_ROOT set to an empty sentinel: 1752 passed / 0 failed / 38
skipped; the sentinel stayed empty, the review worktree had no .mam, and
the main checkout's shim was not touched.

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: 4.8.8
+version: 4.8.9
 author: godopu
 license: MIT
 platforms: [linux, macos]