test: exclude top 15% of viewport from mobile screenshot tests

- Add viewport clipping to mobile baseline tests to reduce flakiness
- Clip top 15% of viewport for all @mobile screenshot tests
- Affects:
  - mobileBaseline.spec.ts: empty canvas and default workflow tests
  - pan.spec.ts: touch pan test
  - move.spec.ts: touch node move test
- This helps reduce test flakiness from variable mobile UI elements

browser_tests/tests/vueNodes/interactions/node/move.spec.ts

@@ -1,8 +1,5 @@
-import {
-  type ComfyPage,
-  comfyExpect as expect,
-  comfyPageFixture as test
-} from '../../../../fixtures/ComfyPage'
+import { comfyExpect as expect, comfyPageFixture as test } from '../../../../fixtures/ComfyPage';
+import type { ComfyPage } from '../../../../fixtures/ComfyPage';
 import type { Position } from '../../../../fixtures/types'
 
 test.describe('Vue Node Moving', () => {
@@ -60,8 +57,20 @@ test.describe('Vue Node Moving', () => {
     const newHeaderPos = await getLoadCheckpointHeaderPos(comfyPage)
     await expectPosChanged(loadCheckpointHeaderPos, newHeaderPos)
 
+    // Get viewport size and clip top 15%
+    const viewportSize = comfyPage.page.viewportSize()
+    const clipRegion = viewportSize
+      ? {
+          x: 0,
+          y: Math.floor(viewportSize.height * 0.15),
+          width: viewportSize.width,
+          height: Math.ceil(viewportSize.height * 0.85)
+        }
+      : undefined
+
     await expect(comfyPage.canvas).toHaveScreenshot(
-      'vue-node-moved-node-touch.png'
+      'vue-node-moved-node-touch.png',
+      { clip: clipRegion }
     )
   })
 })