refactor(ui): simplify AppSwitcher styles and migrate to local SVG icons

- Replace complex gradient animations with clean, minimal tab design
- Migrate from @lobehub/icons CDN to local SVG assets for better reliability
- Fix clippy warning in error.rs (use inline format args)
- Improve code formatting in skill service and commands
- Reduce CSS complexity in AppSwitcher component (removed blur effects and gradients)
- Update BrandIcons to use imported local SVG files instead of dynamic image loading

This improves performance, reduces external dependencies, and provides a cleaner UI experience.

src/lib/errors/skillErrorParser.ts

@@ -70,7 +70,7 @@ function getSuggestionI18nKey(suggestion: string): string {
 export function formatSkillError(
   errorString: string,
   t: TFunction,
-  defaultTitle: string = "skills.installFailed"
+  defaultTitle: string = "skills.installFailed",
 ): { title: string; description: string } {
   const parsedError = parseSkillError(errorString);