test(app): tolerate footer icon subpixel rounding (#5898)

Chromium bounding boxes differ by millionths of a pixel for equal-width footer buttons. Allow less than 0.01px in width and grouped-gap comparisons while preserving alignment and Help/Settings separation checks.

packages/app/e2e/support/helpers/sidebar-nav-settings.ts

@@ -225,6 +225,9 @@ const FOOTER_ICON_TEST_IDS = [
   "sidebar-settings",
 ];
 
+// Browser layout boxes include floating-point rounding, even for whole-pixel styles.
+const FOOTER_GEOMETRY_TOLERANCE = 0.01;
+
 /**
  * One line of same-size icons: Add project, Usage and Hosts together on the left, Help and
  * Settings together at the end.
@@ -240,10 +243,12 @@ export async function expectFooterIconRow(page: Page): Promise<void> {
   const [first] = boxes;
   for (const box of boxes) {
     expect(Math.abs(box.y + box.height / 2 - first!.y - first!.height / 2)).toBeLessThan(2);
-    expect(box.width).toBe(first!.width);
+    expect(Math.abs(box.width - first!.width)).toBeLessThan(FOOTER_GEOMETRY_TOLERANCE);
   }
   const gaps = boxes.slice(1).map((box, index) => box.x - (boxes[index]!.x + boxes[index]!.width));
-  expect(gaps).toEqual([0, 0, expect.any(Number), 0]);
+  for (const index of [0, 1, 3]) {
+    expect(Math.abs(gaps[index]!)).toBeLessThan(FOOTER_GEOMETRY_TOLERANCE);
+  }
   expect(gaps[2]).toBeGreaterThan(first!.width);
 }