fix(web): audio page cover clipping the title

The cover card forced aspect-ratio:1 with overflow:hidden, but the
title + How-to-Listen instructions are taller than the square allowed.
Result: the H1 was cropped and the instructions bled past the gradient
edge. Drop the forced square; let the card size to content.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: mayurpise

web/book/audio/index.html

@@ -42,17 +42,15 @@
         .audio-page-cover-wrapper {
             position: sticky;
             top: 100px;
-            aspect-ratio: 1;
             background: linear-gradient(135deg, #2563eb, #7c3aed);
             border-radius: 32px;
             display: flex;
             flex-direction: column;
             align-items: center;
-            justify-content: center;
+            justify-content: flex-start;
             box-shadow: 0 30px 60px rgba(0,0,0,0.4);
-            padding: 40px;
+            padding: 48px 40px;
             text-align: center;
-            overflow: hidden;
         }
 
         .cover-title {