fix: playlist edit — cover upload in pencil dialog, remove cover-remove button

Android: camera hero button removed; cover upload moved into edit dialog.
Web: trash icon removed from cover actions in edit modal.

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

index.html

@@ -917,9 +917,7 @@
           <button class="edit-pl-cover-btn" onclick="document.getElementById('edit-pl-file').click()" title="Bild hochladen">
             <svg width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2"><path d="M23 19a2 2 0 0 1-2 2H3a2 2 0 0 1-2-2V8a2 2 0 0 1 2-2h4l2-3h6l2 3h4a2 2 0 0 1 2 2z"/><circle cx="12" cy="13" r="4"/></svg>
           </button>
-          <button class="edit-pl-cover-btn" onclick="editPlRemoveCover()" title="Bild entfernen">
-            <svg width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2"><polyline points="3 6 5 6 21 6"/><path d="M19 6l-1 14a2 2 0 0 1-2 2H8a2 2 0 0 1-2-2L5 6"/><path d="M10 11v6"/><path d="M14 11v6"/></svg>
-          </button>
+
         </div>
         <input type="file" id="edit-pl-file" accept="image/*" style="display:none" onchange="editPlCoverSelected(this)">
       </div>