Pin Ruff to v0.15.2 in CI and pre-commit to avoid breakages from
upstream releases. Run Ruff via astral-sh/ruff-action (pinned by SHA)
instead of installing Ruff via pip.
Document where Ruff is pinned and keep the release checklist/style guide
in sync.
Fixes#21472Fixes#21497
* Add a background-color to img elements in docs to ensure readability in dark mode
* Limit style changes to those within CMS content blocks; update colors of main netbox_logo.svg
* Add a white stroke to the main logo
* Add light & dark mode versions of the NetBox logo
---------
Co-authored-by: Jeremy Stretch <jstretch@netboxlabs.com>