readthedocs improvements

[mwarkentin]

Tasks

• Fix the failing build
• Fix auto-builds (webhook / GitHub integration)
• Add versioning support
• Enable pull request previews
• Update README badge to point to stable

Current State

• RTD project: django-watchman.readthedocs.io
• Docs tool: MkDocs with Material theme, using mkdocstrings
• Config: .readthedocs.yaml uses asdf to install uv, then uv sync --frozen --group docs
• Builds: The latest build (#31711977) is passing (state: finished, success: true).
• Releases use semver tags like 1.5.0 (per RELEASING.md)

1. Fix the Failing Build

Build is working. The asdf-based uv installation in .readthedocs.yaml is functioning correctly on RTD's build environment with Python 3.14 and uv 0.10.9.

2. Fix Auto-Builds (Webhook / GitHub Integration)

Configured a manual GitHub webhook. Pushes to main now automatically trigger RTD builds.

3. Add Versioning Support

• Activated stable, 1.4.0, and 1.5.0 versions -- all building successfully
• Created a "Versioned Releases" automation rule with a semver custom match on tags, action: activate version
• Future release tags will be automatically activated and built

4. Enable Pull Request Previews

Enabled "Build pull requests for this project" in RTD settings. PRs now get doc preview builds with status checks on GitHub. Confirmed working on #236.

5. Update README Badge

Updated in #236 to point to stable instead of latest.