feature: theming & dark mode

[adrianthedev]

Description

Closes https://github.com/avo-hq/avo/issues/631 Closes https://github.com/avo-hq/avo/issues/1191

Checklist:

• [ ] I have performed a self-review of my own code
• [ ] I have commented my code, particularly in hard-to-understand areas
• [ ] I have made corresponding changes to the documentation
• [ ] I have added tests that prove my fix is effective or that my feature works

Screenshots & recording

https://github.com/avo-hq/avo/assets/1334409/04d5542f-34f1-47d8-b229-301dfa4ed99d

Manual review steps

1. Step 1
2. Step 2

Manual reviewer: please leave a comment with output from the test if that's the case.

[qlty-cloud-legacy[bot]]

Code Climate has analyzed commit 9328a245 and detected 0 issues on this pull request.

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[adrianthedev]

We might need to wait for Tailwind 4.0

https://twitter.com/adamwathan/status/1758675712800632939?s=46&t=ege6xLvdTHIw1FfCSPTesg

[github-actions[bot]]

This PR has been marked as stale because there was no activity for the past 15 days.

[adrianthedev]

I am quite excited for the new "all CSS variables" Tailwind approach. https://tailwindcss.com/blog/tailwindcss-v4-alpha

[adrianthedev]

Closing for now. Will reopen with Tailwind 4