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.

tools/README.md

@@ -104,6 +104,45 @@ reuse-surface hub sync --dry-run
 
 Run the service locally: `REUSE_SURFACE_TOKEN=dev-token reuse-surface serve`
 
+### stats
+
+Registry maturity aggregates and federation readiness.
+
+```bash
+reuse-surface stats
+reuse-surface stats --format json
+reuse-surface stats --federation-ready --raw-url https://.../capabilities.yaml
+```
+
+### establish
+
+Bootstrap or discover a capability registry in the current or target repo.
+
+```bash
+reuse-surface establish --scaffold --domain helix_forge
+reuse-surface establish --scaffold --path ../state-hub
+reuse-surface establish --publish-check --raw-url https://.../capabilities.yaml
+export LLM_CONNECT_URL=http://127.0.0.1:8088
+reuse-surface establish --discover --dry-run
+reuse-surface establish --discover --apply
+```
+
+`--scaffold` creates `registry/` layout. `--publish-check` probes raw URL and
+local index YAML. `--discover` drafts capabilities via llm-connect (optional).
+
+### update
+
+Refresh registry metadata from repo drift signals.
+
+```bash
+reuse-surface update --capability capability.registry.register --dry-run
+reuse-surface update --all --from-git-since HEAD~5 --apply
+reuse-surface update --capability capability.registry.register --suggest-maturity
+```
+
+Deterministic patches (`vector_drift`, new `tests/` citations) apply with
+`--apply`. LLM suggestions use `--suggest-maturity` and remain review-only.
+
 ### report cohorts
 
 Export capability cohorts for planning or implementation reuse decisions.
@@ -140,6 +179,11 @@ Stable IDs and maturity fields are preserved for agent consumption (UC-RS-019).
 | Publish catalog | `reuse-surface catalog` |
 | Compose federation | `reuse-surface federation compose` |
 | Sync federation manifest from hub | `reuse-surface hub sync` |
+| Registry stats | `reuse-surface stats` |
+| Bootstrap sibling registry | `reuse-surface establish --scaffold` |
+| Verify index publish URL | `reuse-surface establish --publish-check` |
+| Draft capabilities (LLM) | `reuse-surface establish --discover` |
+| Refresh entry metadata | `reuse-surface update` |
 | Planning cohort export | `reuse-surface report cohorts` |
 | Relation graph | `reuse-surface graph` |