feat(FN-966): add new color themes and reduce purple across existing themes

- Add 4 new themes: night-owl, palenight, monokai-pro, slime
- Add one-dark light variant for the existing one-dark theme
- Reduce purple dominance in high-contrast, github-dark, catppuccin-mocha, everforest, and kanagawa themes
- Update workflow badges and step-type-ai-prompt to use non-purple accent colors
- Add new theme IDs to index.html validThemes for flash-of-unstyled-content prevention
- Create changeset for published @gsxdsm/fusion package

packages/core/src/types.ts

@@ -33,6 +33,10 @@ export const COLOR_THEMES = [
   "everforest",
   "rose-pine",
   "kanagawa",
+  "night-owl",
+  "palenight",
+  "monokai-pro",
+  "slime",
 ] as const;
 export type ColorTheme = (typeof COLOR_THEMES)[number];