Finish WEBFETCH-WP-0001: refine SCOPE/INTENT, dev workflow, reuse-surface registry, seed WP-0002

- SCOPE.md rewritten with repo-specific boundaries and current state
- INTENT.md: consumer contract and capability id
- AGENTS.md: developer workflow (test/run/validate)
- registry/: capability.infotech.provenance-fetch (D2/A2/C1/R1)
- workplans: WP-0001 finished, WP-0002 proposed

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

Assistant: claude-code
Assistant-Model: opus
Assistant-Process: 153021@bnt-lap001
Assistant-Session: 46917be4-6400-4106-b8b7-61953a0caf24

INTENT.md

@@ -17,6 +17,11 @@ to pull data from the web and from public APIs.
 5. **Minimal footprint.** Standard library only, so it runs inside executors
    (for example rein-aharness on railiance01) without dependency management.
 
+**Contract.** Consumers depend on the `Observation` fields and the spec
+format documented in `README.md`; adapters may be added freely, but changing
+those fields is a breaking change. Discoverable through reuse-surface as
+`capability.infotech.provenance-fetch`.
+
 Out of scope: crawling, scraping behind logins, LLM-based extraction,
 scheduling (activity-core owns *when*), and execution orchestration
 (rein-aharness owns *how it runs*).