fix scrolling behind full-screen

Author: disnet

frontend/src/lib/components/feed/SavedReader.svelte

@@ -218,13 +218,14 @@
     }
   }
 
-  // Register keydown on document capture phase so the reader intercepts keys
-  // before the global keyboard store (which listens on window bubble phase).
-  // This prevents duplicate tag menus and other shortcut conflicts.
+  // Lock body scroll while reader is open to prevent background list from
+  // scrolling (which can trigger pull-to-refresh prematurely on mobile).
   onMount(() => {
+    document.body.style.overflow = 'hidden';
     document.addEventListener('keydown', handleKeydown, true);
   });
   onDestroy(() => {
+    document.body.style.overflow = '';
     document.removeEventListener('keydown', handleKeydown, true);
   });