test: add Window type augmentation and standardize window access

- Add browser_tests/types/globals.d.ts with Window interface augmentation

- Add types for app, graph, LiteGraph, LGraphBadge and test globals

- Standardize window['prop'] to window.prop across 37 test files

- Update browser_tests/tsconfig.json to include new type definitions

Amp-Thread-ID: https://ampcode.com/threads/T-019c16b3-cc31-70ea-9727-a933cb0ee942
Co-authored-by: Amp <amp@ampcode.com>

browser_tests/helpers/fitToView.ts

@@ -23,7 +23,7 @@ export async function fitToViewInstant(
     { selectionOnly: boolean }
   >(
     ({ selectionOnly }) => {
-      const app = window['app']
+      const app = window.app
       if (!app?.canvas) return null
 
       const canvas = app.canvas
@@ -90,7 +90,7 @@ export async function fitToViewInstant(
 
   await comfyPage.page.evaluate(
     ({ bounds, zoom }) => {
-      const app = window['app']
+      const app = window.app
       if (!app?.canvas) return
 
       const canvas = app.canvas