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/reports/reviewer-grok-01/report-e44ac99c.identity.json

@@ -0,0 +1,14 @@
+{
+  "loop_id": "loop-20260924T085626Z-b8987e",
+  "base_sha": "59be1c89209a232059aec0c5aeecc2329929cb49",
+  "head_sha": "708262a598c4301c0ccc70efba5401093b4b1e30",
+  "tree_sha": "d601c2d01bb4c09931e5e1989e140b01d51f5b96",
+  "review_commit": "708262a598c4301c0ccc70efba5401093b4b1e30",
+  "reviewer": "reviewer-grok-01",
+  "job_id": "e44ac99c",
+  "verdict": "PASS",
+  "transport": "herdr",
+  "evidence": "review-tree",
+  "isolation": "worktree",
+  "verified_at": "2026-09-24T09:09:43Z"
+}