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/vueNodes/interactions/node/bringToFront.spec.ts

@@ -7,9 +7,9 @@ import { fitToViewInstant } from '../../../../helpers/fitToView'
 
 test.describe('Vue Node Bring to Front', { tag: '@screenshot' }, () => {
   test.beforeEach(async ({ comfyPage }) => {
-    await comfyPage.setSetting('Comfy.UseNewMenu', 'Disabled')
-    await comfyPage.setSetting('Comfy.VueNodes.Enabled', true)
-    await comfyPage.loadWorkflow('vueNodes/simple-triple')
+    await comfyPage.settings.setSetting('Comfy.UseNewMenu', 'Disabled')
+    await comfyPage.settings.setSetting('Comfy.VueNodes.Enabled', true)
+    await comfyPage.workflow.loadWorkflow('vueNodes/simple-triple')
     await comfyPage.vueNodes.waitForNodes()
     await fitToViewInstant(comfyPage)
   })
@@ -61,7 +61,7 @@ test.describe('Vue Node Bring to Front', { tag: '@screenshot' }, () => {
     if (!ksamplerHeader) throw new Error('KSampler header not found')
 
     // Drag KSampler on top of CLIP Text Encode
-    await comfyPage.dragAndDrop(
+    await comfyPage.canvasOps.dragAndDrop(
       { x: ksamplerHeader.x + 50, y: ksamplerHeader.y + 10 },
       clipCenter
     )
@@ -108,7 +108,7 @@ test.describe('Vue Node Bring to Front', { tag: '@screenshot' }, () => {
     const vaeHeader = await comfyPage.page.getByText('VAE Decode').boundingBox()
     if (!vaeHeader) throw new Error('VAE Decode header not found')
 
-    await comfyPage.dragAndDrop(
+    await comfyPage.canvasOps.dragAndDrop(
       { x: vaeHeader.x + 50, y: vaeHeader.y + 10 },
       { x: clipCenter.x - 50, y: clipCenter.y }
     )