fix: improve theming and settings visibility

- Fix namespace detail panel to follow system dark/light theme
- Use proper CSS custom properties for background and text colors
- Fix plugin settings registration (remove deprecated third parameter)
- Ensure close button and headers respect theme colors
- Version bump to 0.2.5

Generated with [Claude Code](https://claude.ai/code)
via [Happy](https://happy.engineering)

Co-Authored-By: Claude <noreply@anthropic.com>
Co-Authored-By: Happy <yesreply@happy.engineering>

src/index.tsx

@@ -61,4 +61,5 @@ registerRoute({
   ),
 });
 
-registerPluginSettings('polaris', PolarisSettings, true);
+// Register plugin settings
+registerPluginSettings('polaris', PolarisSettings);