Enhance frontend styling and accessibility features

- Updated .dockerignore to exclude backup directory with root-only permissions from build context.
- Added new CSS variables for card radius and transition duration in app.css.
- Implemented consistent focus ring styles for interactive elements to improve accessibility.
- Refactored card components across various pages to utilize a unified card style, enhancing visual consistency.
- Improved button styles with touch manipulation support for better user interaction on mobile devices.

.dockerignore

@@ -18,6 +18,9 @@ frontend-nuxt/.output
 # Runtime data (mounted at run time, not needed for build)
 grids
 
+# Backup dir often has root-only permissions; exclude from build context
+backup
+
 # Misc
 *.log
 .env*