refactor: improve TypeScript patterns in test files (Group 1/8) (#8253)

## Summary
Improves type safety in test files by replacing unsafe type patterns
with proper TypeScript idioms.

## Changes
- Define typed `TestWindow` interface extending `Window` for Playwright
tests with custom properties
- Use `Partial<HTMLElement>` with single type assertion for DOM element
mocks
- Remove redundant type imports
- Fix `console.log` → `console.warn` in test fixture

## Files Changed
16 test files across browser_tests, packages, and src/components

## Test Plan
- ✅ `pnpm typecheck` passes
- ✅ No new `any` types introduced
- ✅ All pre-commit hooks pass

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-8253-refactor-improve-TypeScript-patterns-in-test-files-Group-1-8-2f16d73d365081548f9ece7bcf0525ee)
by [Unito](https://www.unito.io)

---------

Co-authored-by: coderabbitai[bot] <136622811+coderabbitai[bot]@users.noreply.github.com>

browser_tests/tests/selectionToolboxSubmenus.spec.ts

@@ -1,6 +1,7 @@
 import { expect } from '@playwright/test'
 
 import { comfyPageFixture as test } from '../fixtures/ComfyPage'
+import type { ComfyPage } from '../fixtures/ComfyPage'
 
 test.beforeEach(async ({ comfyPage }) => {
   await comfyPage.setSetting('Comfy.UseNewMenu', 'Disabled')
@@ -15,7 +16,7 @@ test.describe('Selection Toolbox - More Options Submenus', () => {
     await comfyPage.nextFrame()
   })
 
-  const openMoreOptions = async (comfyPage: any) => {
+  const openMoreOptions = async (comfyPage: ComfyPage) => {
     const ksamplerNodes = await comfyPage.getNodeRefsByTitle('KSampler')
     if (ksamplerNodes.length === 0) {
       throw new Error('No KSampler nodes found')