Collapsible Left Panel - Ensure that panels have non-fractional widths (#33052)

* Expand panel to full width

* Write tests

* Resize to nearest whole number if necessary

* Update screenshots

* Early return when resizing to whole width

* Update screenshot

apps/web/src/viewmodels/structures/ResizerViewModel.ts

@@ -57,6 +57,12 @@ export class ResizerViewModel
     }, 50);
 
     public onLeftPanelResized = (newSize: number): void => {
+        // We don't want the panels to have fractional widths as that can cause blurry UI elements.
+        if (!Number.isInteger(newSize)) {
+            this.panelHandle?.resize(`${Math.round(newSize)}%`);
+            return;
+        }
+
         const isCollapsed = newSize === 0;
         // Store the size if the panel isn't collapsed.
         if (!isCollapsed) {