refactor: streamline toast system and harmonize UI across tools

- Migrate all toast notifications to sonner and remove custom ToastProvider
- Align Card and TextInput styling across Figlet and Pastel (rounded-lg, border-based)
- Fix build error by removing non-existent export in lib/units/index.ts
- Clean up unused Figlet components and constants

lib/units/index.ts

@@ -1,4 +1,3 @@
 export * from './units';
 export * from './storage';
-export * from './utils';
 export * from './tempo';