Themes (#45)

* Add new themes and improve theme selection

- Add live theme preview while browsing theme selector
- Add Terminal Default theme (textual-ansi) using terminal's ANSI colors
- Add new custom themes: hackerman, everforest, kanagawa, matte-black, ristretto, osaka-jade, sqlit-light
- Override built-in themes to add proper border contrast (dracula, flexoki, monokai, solarized-dark, tokyo-night, gruvbox, nord, textual-dark)
- Categorize themes into Light and Dark sections in theme selector
- Add hackerman SQL syntax highlighting theme for query editor

* Fix broken themes, persist change on omarchy

* Omarchy fix

* commit

* refactoring

* Remove old screenshots

* More refactor

* UX improvements

* Fix tests

---------

Co-authored-by: Peter Adams <18162810+Maxteabag@users.noreply.github.com>

Author: Maxteabag