feat: redesign public news feed with Apple-inspired premium aesthetic

Complete CSS rewrite implementing a clean, modern design:
- Inter font family with refined typography scale (22px titles, 15px body)
- CSS custom properties for full light/dark mode theming
- Card-based article layout with 8px radius, subtle shadows, hover lift
- Generous spacing and whitespace for premium feel (900px max-width)
- Source badges with background treatment, blue-tinted tag pills
- Staggered skeleton loading animations
- WCAG AA accessible focus states and contrast ratios
- Responsive breakpoints at 480px, 768px, 1024px
- Reduced motion and high contrast media query support
- Version bumped to 2.2.0

Design approved by Design Director (8.5/10), QA verified all
28 .pn-* class names preserved with zero React component changes.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

peptide-news-plugin.php

@@ -3,7 +3,7 @@
  * Plugin Name:       Peptide News Aggregator
  * Plugin URI:        https://github.com/peptiderepo/peptide-news-plugin
  * Description:       Aggregates and displays the latest peptide research news from multiple sources with click analytics and trend reporting.
- * Version:           2.1.0
+ * Version:           2.2.0
  * Author:            Peptide News Team
  * Author URI:        https://github.com/peptiderepo
  * License:           GPL-2.0+
@@ -22,7 +22,7 @@ if ( ! defined( 'WPINC' ) ) {
 /**
  * Current plugin version — follows SemVer.
  */
-define( 'PEPTIDE_NEWS_VERSION', '2.1.0' );
+define( 'PEPTIDE_NEWS_VERSION', '2.2.0' );
 define( 'PEPTIDE_NEWS_PLUGIN_DIR', plugin_dir_path( __FILE__ ) );
 define( 'PEPTIDE_NEWS_PLUGIN_URL', plugin_dir_url( __FILE__ ) );
 define( 'PEPTIDE_NEWS_PLUGIN_BASENAME', plugin_basename( __FILE__ ) );