feat: update theme-rlmm

[ghostrider-05]

Please describe the changes this PR makes and why it should be merged:

• updates dependency versions, including theme updates, and node to v22
• update nav to highlight the current page
• update frontmatter keys & validation
• update guides resource page

What kind of change does this PR introduce? (check at least one)

• Bugfix
• Feature
• Documentation changes
• Build-related changes
• Other, please describe:

The PR fulfills these requirements:

• When resolving a specific issue, it's referenced in the PR's title (e.g. fix #xxx[,#xxx], where "xxx" is the issue number)
• Code changes have been tested locally, or there are no code changes
• I have followed the steps to contribute and followed the guidelines
• If my contribution contains a workflow, I've performed said workflow directly before making the change request and no steps are missing.

Other information

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