fix: virtual scroll flickering on inventory scroll

- Batch scroll renders with requestAnimationFrame to avoid multiple DOM updates per frame
- Add will-change, contain and content-visibility CSS for smoother compositing
- Add cache-bust to virtual-scroll.js

pos/static/css/inventory.css

@@ -1333,6 +1333,20 @@
     /* History table inside modal */
     .inv-modal .data-table { width: 100%; }
 
+    /* ─── Virtual Scroll fixes ───────────────────────────────────────────── */
+    .vs-container {
+      will-change: transform;
+      contain: layout paint;
+      -webkit-overflow-scrolling: touch;
+    }
+    .vs-container table {
+      will-change: transform;
+    }
+    .vs-container tbody tr {
+      content-visibility: auto;
+      contain-intrinsic-size: auto 48px;
+    }
+
     /* ─── MercadoLibre Publish Modal Enhancements ────────────────────────── */
     .meli-preview-card {
       display: grid;