fix: disable ESLint no-unused-vars for Window interface declaration

- Adds eslint-disable-next-line comment for Window interface in renderer.ts
- Window interface extends global Window with ccusageAPI property (Electron pattern)
- Fixes ESLint error causing CI lint step to fail

Co-authored-by: jason <[email protected]>

Author: claude[bot]

src/renderer.ts

@@ -1,3 +1,4 @@
+// eslint-disable-next-line @typescript-eslint/no-unused-vars
 interface Window {
   ccusageAPI: {
       getUsageData: () => Promise<{