refactor: remove underline animation and update styling

- Remove underline-animation UnoCSS shortcut from uno.config.ts
- Update Navbar component to remove underline-animation classes
- Remove inline script for link transition animations
- Add cover images to existing posts
- Update font and date display classes in index pages
- Modify global CSS for iOS rendering optimization

uno.config.ts

@@ -34,28 +34,7 @@ export default defineConfig({
       serif: ['STIX', 'EarlySummer', 'Georgia', 'ui-serif', 'Georgia', 'Cambria', 'Times New Roman', 'Times', 'serif'],
     },
   },
-  shortcuts: {
-    'underline-animation': [
-      'relative',
-      'after:content-empty',
-      'after:absolute',
-      'after:left-0',
-      'after:bottom--1',
-      'after:w-full',
-      'after:h-0.4',
-      'after:bg-secondary',
-      'after:scale-x-0',
-      'after:origin-right',
-      'after:transition-transform',
-      'after:duration-300',
-      'after:ease-out',
-      'hover:after:scale-x-100',
-      'hover:after:origin-left',
-      'transition-ready',
-      '[&.force-leave]:after:scale-x-0',
-      '[&.force-leave]:after:origin-right',
-    ],
-  },
+  shortcuts: {},
   rules: [],
   transformers: [
     transformerDirectives(),