refactor: Extract comfyPageFixture to separate file

Fixes circular dependency between ComfyPage and LocalhostComfyPage.

Changes:
- Create browser_tests/fixtures/comfyPageFixture.ts with fixture
- Remove fixture from ComfyPage.ts (keep abstract class only)
- Re-export fixture from ComfyPage.ts for backward compatibility

Now properly follows dependency hierarchy:
- ComfyPage.ts (abstract) - no implementation imports
- LocalhostComfyPage.ts → imports ComfyPage
- comfyPageFixture.ts → imports both
- Tests import from ComfyPage.ts (re-exported)

browser_tests/fixtures/comfyPageFixture.ts

@@ -0,0 +1,56 @@
+import { test as base } from '@playwright/test'
+
+import { NodeBadgeMode } from '../../src/types/nodeSource'
+import type { ComfyPage } from './ComfyPage'
+import { testComfySnapToGridGridSize } from './ComfyPage'
+import { ComfyMouse } from './ComfyMouse'
+import { LocalhostComfyPage } from './LocalhostComfyPage'
+
+/**
+ * Localhost fixture for ComfyPage.
+ * Creates a test user and sets up default settings for stable testing.
+ */
+export const comfyPageFixture = base.extend<{
+  comfyPage: ComfyPage
+  comfyMouse: ComfyMouse
+}>({
+  comfyPage: async ({ page, request }, use, testInfo) => {
+    const comfyPage = new LocalhostComfyPage(page, request)
+
+    const { parallelIndex } = testInfo
+    const username = `playwright-test-${parallelIndex}`
+    const userId = await comfyPage.setupUser(username)
+    if (userId) {
+      comfyPage.userIds[parallelIndex] = userId
+    }
+
+    try {
+      await comfyPage.setupSettings({
+        'Comfy.UseNewMenu': 'Top',
+        // Hide canvas menu/info/selection toolbox by default.
+        'Comfy.Graph.CanvasInfo': false,
+        'Comfy.Graph.CanvasMenu': false,
+        'Comfy.Canvas.SelectionToolbox': false,
+        // Hide all badges by default.
+        'Comfy.NodeBadge.NodeIdBadgeMode': NodeBadgeMode.None,
+        'Comfy.NodeBadge.NodeSourceBadgeMode': NodeBadgeMode.None,
+        // Disable tooltips by default to avoid flakiness.
+        'Comfy.EnableTooltips': false,
+        'Comfy.userId': userId,
+        // Set tutorial completed to true to avoid loading the tutorial workflow.
+        'Comfy.TutorialCompleted': true,
+        'Comfy.SnapToGrid.GridSize': testComfySnapToGridGridSize,
+        'Comfy.VueNodes.AutoScaleLayout': false
+      })
+    } catch (e) {
+      console.error(e)
+    }
+
+    await comfyPage.setup()
+    await use(comfyPage)
+  },
+  comfyMouse: async ({ comfyPage }, use) => {
+    const comfyMouse = new ComfyMouse(comfyPage)
+    await use(comfyMouse)
+  }
+})