test: add E2E tests for bottom panel core behaviors (#10814)

## Summary
- Add `browser_tests/tests/bottomPanel.spec.ts` with tests for behaviors
not covered by existing `bottomPanelLogs` and `bottomPanelShortcuts`
specs
- Tests cover: close button (X), tab persistence on re-open, resize
gutter visibility and drag, canvas interaction when panel is closed,
cross-panel switching (terminal <-> shortcuts), and registered tab
enumeration
- Extend `BottomPanel` fixture with `closeButton` and `resizeGutter`
locators

## Test plan
- [ ] `pnpm test:browser:local` passes all new tests in
`bottomPanel.spec.ts`
- [ ] Existing `bottomPanelLogs.spec.ts` and
`bottomPanelShortcuts.spec.ts` are unaffected
- [ ] `pnpm typecheck:browser` passes
- [ ] `pnpm lint` passes

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-10814-test-add-E2E-tests-for-bottom-panel-core-behaviors-3366d73d365081ea9b90c643897845fa)
by [Unito](https://www.unito.io)

---------

Co-authored-by: dante <dante@danteui-MacStudio.local>
Co-authored-by: GitHub Action <action@github.com>
Co-authored-by: Alexander Brown <drjkl@comfy.org>

browser_tests/tests/bottomPanel.spec.ts

@@ -0,0 +1,102 @@
+import {
+  comfyPageFixture as test,
+  comfyExpect as expect
+} from '@e2e/fixtures/ComfyPage'
+
+test.describe('Bottom Panel', { tag: '@ui' }, () => {
+  test.beforeEach(async ({ comfyPage }) => {
+    await comfyPage.settings.setSetting('Comfy.UseNewMenu', 'Top')
+  })
+
+  test('should close panel via close button inside the panel', async ({
+    comfyPage
+  }) => {
+    const { bottomPanel } = comfyPage
+
+    await bottomPanel.toggleButton.click()
+    await expect(
+      bottomPanel.root,
+      'Panel should be open before testing close button'
+    ).toBeVisible()
+
+    await bottomPanel.closeButton.click()
+    await expect(bottomPanel.root).toBeHidden()
+  })
+
+  test('should display resize gutter when panel is open', async ({
+    comfyPage
+  }) => {
+    const { bottomPanel } = comfyPage
+
+    await bottomPanel.toggleButton.click()
+    await expect(
+      bottomPanel.root,
+      'Panel should be open before checking the resize gutter'
+    ).toBeVisible()
+    await expect(bottomPanel.resizeGutter).toBeVisible()
+  })
+
+  test('should hide resize gutter when panel is closed', async ({
+    comfyPage
+  }) => {
+    const { bottomPanel } = comfyPage
+
+    await expect(bottomPanel.root).toBeHidden()
+    await expect(bottomPanel.resizeGutter).toBeHidden()
+  })
+
+  test('should resize panel by dragging the gutter', async ({ comfyPage }) => {
+    const { bottomPanel } = comfyPage
+
+    await bottomPanel.toggleButton.click()
+    await expect(
+      bottomPanel.root,
+      'Panel should be open before resizing'
+    ).toBeVisible()
+
+    const initialHeight = await bottomPanel.root.evaluate(
+      (el) => el.getBoundingClientRect().height
+    )
+
+    await bottomPanel.resizeByDragging(-100)
+
+    await expect
+      .poll(
+        () =>
+          bottomPanel.root.evaluate((el) => el.getBoundingClientRect().height),
+        {
+          message:
+            'Panel height should increase after dragging the resize gutter'
+        }
+      )
+      .toBeGreaterThan(initialHeight)
+  })
+
+  test('should not block canvas interactions when panel is closed', async ({
+    comfyPage
+  }) => {
+    const { bottomPanel } = comfyPage
+
+    await expect(bottomPanel.root).toBeHidden()
+
+    await comfyPage.canvas.click({
+      position: { x: 100, y: 100 }
+    })
+    await expect(comfyPage.canvas).toHaveFocus()
+  })
+
+  test('should close panel via close button from shortcuts view', async ({
+    comfyPage
+  }) => {
+    const { bottomPanel } = comfyPage
+
+    await bottomPanel.keyboardShortcutsButton.click()
+    await expect(
+      bottomPanel.root,
+      'Panel should be open before closing it from the shortcuts view'
+    ).toBeVisible()
+
+    await bottomPanel.closeButton.click()
+    await expect(bottomPanel.root).toBeHidden()
+  })
+})