Publish topic guides to the wiki and document tabbed windows

Publish the guides from this repository to the GitHub Wiki. Organize them into Usage, Configuration and Development, with 15 separate configuration topics and redirects for the former website guide URLs.

Add a tabbed-windows guide covering grouping, switching tabs and taking windows out. Document the scrolling indicator's defaults and limits, and link the guide from the README, shortcuts and IPC pages. Update from main, including the latest tabbed-layout changes.

Separate Activities setup, configuration and publishing documentation. Review the guide prose with the unslop skill, keeping existing examples and heading links. The wiki workflow uses GitHub's built-in token to publish documentation changes on main.

Validation:

- 20 documentation tests pass, including README links and Activities/tab-indicator field coverage.
- The publisher builds 46 wiki pages; the site build and Python syntax checks pass.
- All 115 code examples from main are preserved.
- The Python suite passes: 90 tests passed and 31 opt-in integration tests skipped, with the system GI module available.

.github/workflows/pages.yml

@@ -12,7 +12,7 @@ jobs:
     steps:
       - uses: actions/checkout@v6
       - uses: actions/configure-pages@v5
-      - name: Build website and handbook
+      - name: Build homepage and documentation redirects
         run: |
           python3 -m venv .site-venv
           .site-venv/bin/pip install -r site/requirements.txt