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/fixtures/helpers/SubgraphHelper.ts

@@ -27,7 +27,7 @@ export class SubgraphHelper {
     const foundSlot = await this.page.evaluate(
       async (params) => {
         const { slotType, action, targetSlotName } = params
-        const app = window['app']
+        const app = window.app
         const currentGraph = app.canvas.graph
 
         // Check if we're in a subgraph