Implement REUSE-WP-0013 registry establish, update, and stats

Add stats, establish (scaffold, publish-check, discover), and update CLI
commands with optional llm-connect bridge, validate --root for sibling repos,
pytest coverage, and documentation for sibling registry onboarding.

registry/README.md

@@ -35,6 +35,21 @@ registry/
 
 Missing evidence is acceptable in the MVP when it is explicit rather than hidden.
 
+## LLM-assisted discover review checklist
+
+When using `reuse-surface establish --discover` (llm-connect backend):
+
+- [ ] Every proposed `id` follows `capability.<domain>.<name>` and is not a duplicate
+- [ ] `summary`, `discovery.intent`, and maturity vectors match repo reality
+- [ ] `owner` reflects the delivering repository or team
+- [ ] Relations are empty or manually added after human review
+- [ ] Run `reuse-surface validate --root <repo>` before merge
+- [ ] Run `reuse-surface establish --publish-check` after pushing to `main`
+
+Discover drafts start at low maturity with explicit auto-draft risks in
+`known_reliability_risks`. Promote only with evidence per
+`specs/CapabilityMaturityStandard.md`.
+
 ## Manual validation checklist
 
 Use this checklist until an automated CLI validator exists.