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/vite-env.d.ts

@@ -0,0 +1,13 @@
+/// <reference types="vite/client" />
+
+interface ImportMetaEnv {
+  readonly DEV: boolean
+  readonly MODE: string
+  readonly BASE_URL: string
+  readonly PROD: boolean
+  readonly SSR: boolean
+}
+
+interface ImportMeta {
+  readonly env: ImportMetaEnv
+}