release(v4.7.3): bump framework and eight skills to 4.7.3 in lockstep; archive PR #37 merge-side reviews

Issue #36: delegated prompts travel by file, a delegation that fails ends
the loop with rc 1. VERSIONS.md carries the entry; the merge-side reports
(round 1 @59be1c8 and round 2 @708262a with identity sidecars, base
59be1c8 -> head 708262a, evidence review-tree) are archived under
.agents/reports/<session>/.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01VCgu9Fa9iT7TbJUSzdq4Ff

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

@@ -1,7 +1,7 @@
 ---
 name: multi-agent-mux-monitor
 description: "Run a long-lived reconciler that watches .mam/agent-sessions.yaml against the actual herdr/agent runtime state and reconciles them. Use when you want live visibility into which agent sessions are running, which are dead, which have stale YAML entries, and which have new session ids that haven't been recorded yet. Runs as a persistent loop (`reconcile.sh --subscribe`) that keeps going until it times out, idles out, or is interrupted."
-version: 4.7.2
+version: 4.7.3
 author: godopu
 license: MIT
 platforms: [linux, macos]