add developer docs

docs-site/docs/developer/editing-documentation.md

@@ -0,0 +1,29 @@
+# Editing this documentation
+
+## Local setup
+
+```bash
+cd docs-site
+python3 -m venv .venv
+source .venv/bin/activate   # Windows: .venv\Scripts\activate
+pip install -r requirements.txt
+mkdocs serve
+```
+
+Open `http://127.0.0.1:8000` and edit files under `docs-site/docs/`. The site reloads on save.
+
+## Conventions
+
+- Use **admonitions** for legal and safety notes (`!!! warning` for proprietary / leak context).
+- Prefer **relative links** between pages (`../reference/cli-entry.md` in source becomes sibling URLs when built).
+- Add **mermaid** only where diagrams clarify flow; keep [mermaid syntax](https://mermaid.js.org/) compatible with [Material diagrams](https://squidfunk.github.io/mkdocs-material/reference/diagrams/).
+
+## After structural changes
+
+If you add a **new top-level topic** that appears in [Anthropic’s docs index](https://code.claude.com/docs/llms.txt), add a row to [Official docs map](../official-docs-map.md).
+
+## Publishing
+
+Pushing to `main` runs the GitHub Action that deploys to `gh-pages`. Ensure `site_url` in `mkdocs.yml` matches your GitHub Pages base URL.
+
+See also: [Documentation and CI for your own projects](../guides/documentation-and-ci-for-docs.md).