#260 (fix attempt 2): static-width copy feedback via .swapbtn

internal/web/templates/paste.html

@@ -8,8 +8,8 @@
       <div class="spacer"></div>
       <button type="button" class="iconbtn wrap-toggle" title="Toggle line wrap" aria-pressed="false">Wrap</button>
       <a class="iconbtn" href="/raw/{{.ID}}">Raw</a>
-      <a class="iconbtn" href="#" id="copy-link-btn">Link</a>
-      <a class="iconbtn" href="#" id="copy-btn">Copy</a>
+      <a class="iconbtn swapbtn" href="#" id="copy-link-btn"><span class="swap-label">Link</span><span class="swap-check">✓</span></a>
+      <a class="iconbtn swapbtn" href="#" id="copy-btn"><span class="swap-label">Copy</span><span class="swap-check">✓</span></a>
       {{if .DeletionToken}}<a class="iconbtn danger" href="#" id="delete-btn">Delete</a>{{end}}
     </div>
   </div>