Update package versions

[wwarriner]

Pull Request

Intent

Get package versions up to date and fix a few other minor issues.

THIS PR will require you to rebuild your local conda environments when merged.

Proposed Changes

• Update packages used in pre-commit
• Update packages used in build and dev environments
• Update packages used in CI/CD
• Add markdownlint-cli2 and related package.json using npm
• Update recommended vscode extensions
• Update link checker script to use polars instead of pandas
• Fix broken links and surrounding context
• Fix front page rendering issue when no announcements are present

Changes to Section Headers

Changes to Page URLs

Related or Fixed Issues

Fixes #1233

Accessibility Checklist

I have ensured all of the following for new or changed content:

• all images have appropriate alt text. Guidelines
• all images with text have sufficient contrast ratio. Checker
• all image text is transcribed or described in body text.
• all technical terms, jargon, and abbreviations are introduced before they are used.

Style Checklist

I have done all of the following:

• searched for other relevant pages and crosslinked from my content to them.
• searched for other relevant pages and crosslinked from them to my content.
• added redirects in mkdocs.yml for any moved headers or pages.
• defined new technical terms, jargon, and abbreviations in the glossary.
• searched for existing technical terms, jargon, and abbreviations in the glossary and added crosslinks to them.
• properly formatted and introduced key branding terms. List here.

[bdu-birhanu]

I tested following the steps we discussed in our sprint meeting, and and the GitHub Actions passed.

Good to merge.