Preview for filter by category LUA filter alternative + add category-filter extension to repo

[nrichers]

Pull Request Description

What and why?

Preview for LUA filter alternative + Add the category-filter extension to the repo so it is available during docs builds.

How to test

What needs special review?

Dependencies, breaking changes, and deployment notes

Release notes

Checklist

• What and why
• Screenshots or videos (Frontend)
• How to test
• What needs special review
• Dependencies, breaking changes, and deployment notes
• Labels applied
• PR linked to Shortcut
• Unit tests added (Backend)
• Tested locally
• Documentation updated (if required)
• Environment variable additions/changes documented (if required)

[validbeck]

Too many PRs, got confused. I get why the filter doesn't work now for my other preview.

[github-actions]

PR Summary

This PR introduces a new category filter extension designed for integrating configuration data from the YAML frontmatter of documents into the rendered HTML. Specifically, the extension reads a property called listing-filter from the metadata, converts it into native Lua types using the helper function meta_to_native, and encodes the result to JSON. It then escapes single quotes and injects the JSON configuration into a hidden <div> element on the page. This enables client-side scripts to access and utilize the configuration for filtering listings on the site.

Key functional changes include:

• Addition of a .quartoignore rule to exclude certain file patterns (e.g., **/*.Rmd).
• A new extension descriptor file (_extension.yml) that registers the extension with its title, author, version, and contribution details.
• Implementation of the meta_to_native function which recursively converts the YAML-frontmatter values to Lua native types, handling cases such as arrays and text blocks.
• The main Meta function that checks if the listing-filter metadata is present, encodes it as JSON, escapes problematic characters, and injects the configuration into the HTML output via an "after-body" file inclusion.

Test Suggestions

• Verify that when a valid 'listing-filter' is provided, the JSON configuration is correctly injected into the HTML without errors.
• Test the behavior when 'listing-filter' is absent to ensure no extraneous hidden div is created.
• Create unit tests for the meta_to_native function with a variety of data types (e.g., string, number, boolean, arrays, nested objects) including empty or nil cases.
• Ensure proper escaping of single quotes in the JSON output to prevent issues in HTML rendering.
• Simulate frontmatter containing pandoc List, Inlines, and Blocks types to verify proper conversion to native values.

[github-actions]

Validate docs site

✓ INFO: A live preview of the docs site is available — Open the preview

[github-actions]

Lighthouse check results

⚠️ WARN: Average accessibility score is 0.87 (required: >0.9) — Check the workflow run

Show Lighthouse scores

Folder depth level checked: 0

Commit SHA: c7cb5d1

Modify the workflow to check a different depth:

• 0: Top-level navigation only — /index.html, /guide/guides.html, ...
• 1: All first-level subdirectories — /guide/.html, /developer/.html, ...
• 2: All second-level subdirectories — /guide/attestation/*.html, ...

Page	Accessibility	Performance	Best Practices	SEO
/developer/validmind-library.html	0.85	0.69	1.00	0.82
/get-started/get-started.html	0.85	0.72	1.00	0.73
/guide/guides.html	0.81	0.71	1.00	0.82
/index.html	0.93	0.67	1.00	0.82
/releases/all-releases.html	0.86	0.69	1.00	0.73
/support/support.html	0.91	0.68	1.00	0.82
/training/training.html	0.85	0.63	0.96	0.73