fix(list): toggle a checkbox in place instead of rebuilding the grid

renderGrid replaces every card, so the scroll container jumped back to the top: ticking a card near the bottom of a long list threw the user back to the first row. Only the affected card and the selection bar are updated now.

js/app.js

@@ -3573,7 +3573,23 @@ let selectionAnchor = null;  // last single-clicked card, used for shift+click r
 function toggleChecked(id) {
     if (state.checked.has(id)) state.checked.delete(id);
     else state.checked.add(id);
-    renderGrid();
+    // In place, not renderGrid(): rebuilding the grid replaces every card, and
+    // the scroll container jumps back to the top — ticking a card near the
+    // bottom of a long list threw the user back to the first row.
+    const on = state.checked.has(id);
+    document.querySelectorAll(
+        '.entry-card[data-id="' + id + '"], .entry-row[data-id="' + id + '"]'
+    ).forEach(node => {
+        node.classList.toggle('is-checked', on);
+        const box = node.querySelector('.entry-check');
+        if (!box) return;
+        box.classList.toggle('is-checked', on);
+        box.title = on ? 'Deselect' : 'Select';
+        // The tick is a child element added at render time, not CSS content.
+        box.textContent = '';
+        if (on) box.appendChild(el('span', null, '✓'));
+    });
+    renderBatchBar();
 }
 
 function handleCardClick(ev, entry, inTrash) {