test(browser): refactor browser tests for reliability and maintainability (#8510)

## Summary

Major refactoring of browser tests to improve reliability,
maintainability, and type safety.

## Changes

### Test Infrastructure Decomposition
- Decomposed `ComfyPage.ts` (~1000 lines) into focused helpers:
- `CanvasHelper`, `DebugHelper`, `SubgraphHelper`,
`NodeOperationsHelper`
- `SettingsHelper`, `WorkflowHelper`, `ClipboardHelper`,
`KeyboardHelper`
- Created `ContextMenu` page object, `BaseDialog` base class, and
`BottomPanel` page object
- Extracted `DefaultGraphPositions` constants

### Locator Stability
- Added `data-testid` attributes to Vue components (sidebar, dialogs,
node library)
- Created centralized `selectors.ts` with test ID constants
- Replaced fragile CSS selectors (`.nth()`, `:nth-child()`) with
`getByTestId`/`getByRole`

### Performance & Reliability
- Removed `setTimeout` anti-patterns (replaced with `waitForFunction`)
- Replaced `waitForTimeout` with retrying assertions
- Replaced hardcoded coordinates with computed `NodeReference` positions
- Enforced LF line endings for all text files

### Type Safety
- Enabled `no-explicit-any` lint rule for browser_tests via oxlint
- Purged `as any` casts from browser_tests
- Added Window type augmentation for standardized window access
- Added proper type annotations throughout

### Bug Fixes
- Restored `ExtensionManager` API contract
- Removed test-only settings from production schema
- Fixed flaky selectors and missing test setup

## Testing
- All browser tests pass
- Typecheck passes


<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit

* **Tests**
* Overhauled browser E2E test infrastructure with many new
helpers/fixtures, updated test APIs, and CI test container image bumped
for consistency.

* **Chores**
* Standardized line endings and applied stricter lint rules for browser
tests; workspace dependency version updated.

* **Documentation**
* Updated Playwright and TypeScript testing guidance and test-run
commands.

* **UI**
* Added stable data-testids to multiple components to improve
testability.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

---------

Co-authored-by: Amp <amp@ampcode.com>
Co-authored-by: GitHub Action <action@github.com>
Co-authored-by: github-actions <github-actions@github.com>
Co-authored-by: coderabbitai[bot] <136622811+coderabbitai[bot]@users.noreply.github.com>

browser_tests/tests/propertiesPanel/propertiesPanelPosition.spec.ts

@@ -1,6 +1,7 @@
 import { expect } from '@playwright/test'
 
 import { comfyPageFixture as test } from '../../fixtures/ComfyPage'
+import { TestIds } from '../../fixtures/selectors'
 
 test.describe('Properties panel position', () => {
   test.beforeEach(async ({ comfyPage }) => {
@@ -12,10 +13,12 @@ test.describe('Properties panel position', () => {
   test('positions on the right when sidebar is on the left', async ({
     comfyPage
   }) => {
-    await comfyPage.setSetting('Comfy.Sidebar.Location', 'left')
+    await comfyPage.settings.setSetting('Comfy.Sidebar.Location', 'left')
     await comfyPage.nextFrame()
 
-    const propertiesPanel = comfyPage.page.getByTestId('properties-panel')
+    const propertiesPanel = comfyPage.page.getByTestId(
+      TestIds.propertiesPanel.root
+    )
     const sidebar = comfyPage.page.locator('.side-bar-panel').first()
 
     await expect(propertiesPanel).toBeVisible()
@@ -36,10 +39,12 @@ test.describe('Properties panel position', () => {
   test('positions on the left when sidebar is on the right', async ({
     comfyPage
   }) => {
-    await comfyPage.setSetting('Comfy.Sidebar.Location', 'right')
+    await comfyPage.settings.setSetting('Comfy.Sidebar.Location', 'right')
     await comfyPage.nextFrame()
 
-    const propertiesPanel = comfyPage.page.getByTestId('properties-panel')
+    const propertiesPanel = comfyPage.page.getByTestId(
+      TestIds.propertiesPanel.root
+    )
     const sidebar = comfyPage.page.locator('.side-bar-panel').first()
 
     await expect(propertiesPanel).toBeVisible()
@@ -60,10 +65,12 @@ test.describe('Properties panel position', () => {
   test('close button icon updates based on sidebar location', async ({
     comfyPage
   }) => {
-    const propertiesPanel = comfyPage.page.getByTestId('properties-panel')
+    const propertiesPanel = comfyPage.page.getByTestId(
+      TestIds.propertiesPanel.root
+    )
 
     // When sidebar is on the left, panel is on the right
-    await comfyPage.setSetting('Comfy.Sidebar.Location', 'left')
+    await comfyPage.settings.setSetting('Comfy.Sidebar.Location', 'left')
     await comfyPage.nextFrame()
 
     await expect(propertiesPanel).toBeVisible()
@@ -74,7 +81,7 @@ test.describe('Properties panel position', () => {
     await expect(closeButtonLeft).toHaveClass(/lucide--panel-right/)
 
     // When sidebar is on the right, panel is on the left
-    await comfyPage.setSetting('Comfy.Sidebar.Location', 'right')
+    await comfyPage.settings.setSetting('Comfy.Sidebar.Location', 'right')
     await comfyPage.nextFrame()
 
     const closeButtonRight = propertiesPanel