release(v4.8.4): bump framework and eight skills to 4.8.4 in lockstep; archive PR #47 reviews (two rounds)

The .claude/skills check accepts both local layouts and fails on a dangling
link. Review: round 1 (@e1ed270) claude agy grok PASS, codex NOT PASS (a
dangling top-level link was skipped); fixed in 150b493; round 2 4/4 PASS.
Reports and the round-2 identity sidecars go to .agents/reports/<session>/.

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: 4.8.3
+version: 4.8.4
 author: godopu
 license: MIT
 platforms: [linux, macos]