feat(frontend): add API client, layout, and routing

- Create Axios-based API client with sources, jobs, and dashboard endpoints
- Add responsive Layout component with navigation sidebar
- Set up React Router with Dashboard, Backups, and Settings routes
- Configure TanStack Query provider with default options
- Use lucide-react for navigation icons

frontend/node_modules/cac/deno/deno.ts

@@ -0,0 +1,4 @@
+// Ignore the TypeScript errors
+// Since this file will only be used in Deno runtime
+export const processArgs = ['deno', 'cli'].concat(Deno.args);
+export const platformInfo = `${Deno.build.os}-${Deno.build.arch} deno-${Deno.version.deno}`;