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>

reuse_surface/registry.py

@@ -87,4 +87,13 @@ def entry_vector(front_matter: dict[str, Any]) -> str:
 
 
 def vectors_match(index_vector: str, front_matter: dict[str, Any]) -> bool:
-    return index_vector.replace(" ", "") == entry_vector(front_matter).replace(" ", "")
+    return index_vector.replace(" ", "") == entry_vector(front_matter).replace(" ", "")
+
+
+def resolve_repo_root(explicit: str | Path | None = None) -> Path:
+    if explicit:
+        return Path(explicit).resolve()
+    cwd = Path.cwd()
+    if (cwd / "registry" / "indexes" / "capabilities.yaml").is_file():
+        return cwd.resolve()
+    return ROOT