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/tests/useSettingSearch.spec.ts

@@ -10,7 +10,7 @@ test.describe('Settings Search functionality', { tag: '@settings' }, () => {
   test.beforeEach(async ({ comfyPage }) => {
     // Register test settings to verify hidden/deprecated filtering
     await comfyPage.page.evaluate(() => {
-      window['app'].registerExtension({
+      window.app.registerExtension({
         name: 'TestSettingsExtension',
         settings: [
           {