fix(a11y): revert touch-only copy button visibility to fix target-size violation

The @media (hover: none) block that made copy buttons always visible on
touch caused the absolutely-positioned button (top: 100%) to appear between
the package header and the sticky subheader, landing within 24px of the
provenance shield link and failing the target-size audit.

Revert to display: none on touch devices to eliminate the overlap.

Author: thegreatalxx

app/components/CopyToClipboardButton.vue

@@ -89,17 +89,9 @@ function handleClick() {
 }
 
 @media (hover: none) {
-  /* On touch devices show the button statically (no hover possible) */
+  /* On touch devices, hide the button since hover is not available */
   .copyButton {
-    clip: auto;
-    clip-path: none;
-    height: auto;
-    overflow: visible;
-    width: auto;
-    opacity: 1;
-    translate: none;
-    pointer-events: auto;
-    transition: none;
+    display: none;
   }
 }
 </style>