fix: mobile touch-action and delete button visibility

- Add touch-action: none to #right-panel for reliable custom
  touch handling
- Show delete button on mobile (no hover state on touch devices)

Co-Authored-By: Claude Opus 4.6 <[email protected]>

unredact/static/style.css

@@ -275,6 +275,7 @@ main {
   border-radius: 8px;
   cursor: grab;
   position: relative;
+  touch-action: none;
 }
 
 #right-panel.panning {
@@ -893,4 +894,9 @@ main {
     height: 2.2rem;
     font-size: 0.9rem;
   }
+
+  /* Delete button: always visible on touch (no hover) */
+  .redaction-delete {
+    opacity: 1;
+  }
 }