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/nodeHelp.spec.ts

@@ -2,15 +2,17 @@ import {
   comfyExpect as expect,
   comfyPageFixture as test
 } from '../fixtures/ComfyPage'
+import type { ComfyPage } from '../fixtures/ComfyPage'
 import { fitToViewInstant } from '../helpers/fitToView'
+import type { NodeReference } from '../fixtures/utils/litegraphUtils'
 
 // TODO: there might be a better solution for this
 // Helper function to pan canvas and select node
-async function selectNodeWithPan(comfyPage: any, nodeRef: any) {
+async function selectNodeWithPan(comfyPage: ComfyPage, nodeRef: NodeReference) {
   const nodePos = await nodeRef.getPosition()
 
   await comfyPage.page.evaluate((pos) => {
-    const app = window['app']
+    const app = window['app']!
     const canvas = app.canvas
     canvas.ds.offset[0] = -pos.x + canvas.canvas.width / 2
     canvas.ds.offset[1] = -pos.y + canvas.canvas.height / 2 + 100
@@ -345,7 +347,7 @@ This is documentation for a custom node.
 
       // Find and select a custom/group node
       const nodeRefs = await comfyPage.page.evaluate(() => {
-        return window['app'].graph.nodes.map((n: any) => n.id)
+        return window['app']!.graph!.nodes.map((n) => n.id)
       })
       if (nodeRefs.length > 0) {
         const firstNode = await comfyPage.getNodeRefById(nodeRefs[0])