feat: add tests and implementation for issue discovery and queue pages

- Implemented `DiscoveryPage` with session management and findings display.
- Added tests for `DiscoveryPage` to ensure proper rendering and functionality.
- Created `QueuePage` for managing issue execution queues with stats and actions.
- Added tests for `QueuePage` to verify UI elements and translations.
- Introduced `useIssues` hooks for fetching and managing issue data.
- Added loading skeletons and error handling for better user experience.
- Created `vite-env.d.ts` for TypeScript support in Vite environment.

ccw/frontend/src/components/issue/discovery/index.ts

@@ -0,0 +1,7 @@
+// ========================================
+// Discovery Components Index
+// ========================================
+
+export { DiscoveryCard } from './DiscoveryCard';
+export { DiscoveryDetail } from './DiscoveryDetail';
+export { FindingList } from './FindingList';