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>

SCOPE.md

@@ -68,6 +68,8 @@ The MVP registry foundation, CLI tooling (REUSE-WP-0003), federation stack
   `--roster registry/federation/local-repo-roster.yaml --federation-ready`)
 - **Draft or refresh entries** with `reuse-surface establish --discover` and
   `reuse-surface update` (optional llm-connect backend)
+- **Maintain registry interactively or automatically** with `reuse-surface maintain`
+  (TTY prompts, `--auto`, optional llm-connect, `--publish` chain)
 - **Run the hub locally or in a container** with `reuse-surface serve`
 - **Generate relation graphs** with `reuse-surface graph`
 - **Explore relations interactively** at `docs/graph/index.html`