WP-0016 finished: interactive registry maintain with llm-connect automation

Closes the registry maintenance loop from inside each domain repo:
interactive prompting for judgment calls, full automation for safe and
high-confidence changes, both backed by the llm-connect HTTP bridge.

- New modules: maintain.py, maintain_llm.py, patches.py, interactive.py
- Schema: schemas/registry-patch.schema.json
- CLI: reuse-surface maintain; establish --scaffold --hook
- Sibling templates: Makefile fragment, pre-commit hook
- Deterministic signal collectors extended; validate cwd auto-detect
- Docs, gap priority 28, SCOPE update
- Tests: test_maintain.py, test_interactive.py (59 pytest total)

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

docs/RegistryFederation.md

@@ -129,12 +129,27 @@ completes the establishment checklist below.
 cd ../state-hub
 reuse-surface establish --scaffold --domain helix_forge
 # optional: LLM_CONNECT_URL=... reuse-surface establish --discover --dry-run
-reuse-surface validate --root .
+reuse-surface validate
 git push origin main
 reuse-surface establish --publish-check \
   --raw-url https://gitea.coulomb.social/coulomb/state-hub/raw/main/registry/indexes/capabilities.yaml
 ```
 
+### Ongoing maintenance (from sibling repo)
+
+```bash
+export LLM_CONNECT_URL=http://127.0.0.1:8088   # optional
+reuse-surface maintain --all --from-git-since origin/main
+reuse-surface maintain --all --auto --no-llm    # CI / pre-commit
+reuse-surface maintain --publish \
+  --raw-url https://gitea.coulomb.social/coulomb/state-hub/raw/main/registry/indexes/capabilities.yaml \
+  --all --auto --no-llm
+```
+
+Copy `templates/Makefile.registry.fragment` for `make registry-maintain` /
+`make registry-check`. Optional pre-commit hook:
+`reuse-surface establish --scaffold --hook`.
+
 ### Registration checklist
 
 1. Merge capability index to the default branch.