feat: docs reference generates a skill catalogue and a page-type reference under docs/reference/ from the shipped defaults, checked and written in the origin repo only (#189)

Files changed:
- CHANGES.md
- README.md
- VERSION
- docs/reference/README.md
- docs/reference/commands/README.md
- docs/reference/commands/types-instructions-and-docs.md
- docs/reference/page-types.md
- docs/reference/skills.md
- instructions/dev/doc-pull-through.md
- tools/CONTRACT.md
- tools/README.md
- tools/chemenu/commands/docs_verify.py
- tools/chemenu/reference_doc.py
- tools/chemenu/tests/test_reference_doc.py

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01SnAJ7Z3CpVD3PRbN73QtU2

docs/reference/commands/README.md

@@ -123,7 +123,7 @@ Full records: [types-instructions-and-docs.md](types-instructions-and-docs.md)
 - [`docs toc`](types-instructions-and-docs.md#docs-toc) - Create, refresh or remove the generated table-of-contents region.
 - [`docs prerequisites`](types-instructions-and-docs.md#docs-prerequisites) - Regenerate `INSTALL.md`'s prerequisites lists from `tools/prerequisites.txt`.
 - [`docs contract`](types-instructions-and-docs.md#docs-contract) - Regenerate `tools/CONTRACT.md`'s `<!-- wikitool:commands -->` region.
-- [`docs reference`](types-instructions-and-docs.md#docs-reference) - Regenerate the human command reference under `docs/reference/`.
+- [`docs reference`](types-instructions-and-docs.md#docs-reference) - Regenerate the human reference under `docs/reference/`.
 
 ## Telemetry