Add top margin to homepage stat card; minor whitespace cleanup

- components/_cards.scss: .stat-card gets margin-top: 2rem; rebuilt
  styles.css to match.
- index.php: strip trailing whitespace on a blank line in the music
  section.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

index.php

@@ -200,7 +200,7 @@ $siteUrl = rtrim(SITE_URL, '/');
     <section id="music" class="music">
       <div class="container">
         <div class="rule-row reveal"><span class="line"></span><img class="knot" src="./assets/knot.png" alt=""><span class="line"></span></div>
-        
+
         <div class="music-grid">
           <div class="music-photo-wrap reveal">
             <img src="./assets/jesse-hart.jpg" alt="Jesse Hart performing live acoustic music" class="music-photo" loading="lazy">