Done! I've changed block: 'nearest' to block: 'start' in ChangesPanelContainer.tsx:168. (#1869)

**What this fixes:**
- `block: 'nearest'` only scrolled the minimum distance to make the element visible, which often left users "halfway" through a file
- `block: 'start'` aligns the top of the selected diff with the top of the scroll container, ensuring the file header is always visible at the top

frontend/src/components/ui-new/containers/ChangesPanelContainer.tsx

@@ -165,7 +165,7 @@ export function ChangesPanelContainer({
     const timeoutId = setTimeout(() => {
       diffRefs.current.get(selectedFilePath)?.scrollIntoView({
         behavior: 'smooth',
-        block: 'nearest',
+        block: 'start',
       });
     }, 0);