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/vitest/dist/browser.d.ts

@@ -0,0 +1,60 @@
+export { processError, startTests } from '@vitest/runner';
+import { R as ResolvedConfig, C as CoverageOptions, b as CoverageProvider, c as CoverageProviderModule } from './reporters-w_64AS5f.js';
+import { VitestExecutor } from './execute.js';
+import 'vite';
+import 'vite-node';
+import '@vitest/snapshot';
+import '@vitest/expect';
+import '@vitest/runner/utils';
+import '@vitest/utils';
+import 'tinybench';
+import 'node:stream';
+import 'vite-node/client';
+import '@vitest/snapshot/manager';
+import 'vite-node/server';
+import 'node:worker_threads';
+import 'node:fs';
+import 'chai';
+import 'node:vm';
+
+type Formatter = (input: string | number | null | undefined) => string;
+
+interface DiffOptions {
+    aAnnotation?: string;
+    aColor?: Formatter;
+    aIndicator?: string;
+    bAnnotation?: string;
+    bColor?: Formatter;
+    bIndicator?: string;
+    changeColor?: Formatter;
+    changeLineTrailingSpaceColor?: Formatter;
+    commonColor?: Formatter;
+    commonIndicator?: string;
+    commonLineTrailingSpaceColor?: Formatter;
+    contextLines?: number;
+    emptyFirstOrLastLinePlaceholder?: string;
+    expand?: boolean;
+    includeChangeCounts?: boolean;
+    omitAnnotationLines?: boolean;
+    patchColor?: Formatter;
+    compareKeys?: any;
+    truncateThreshold?: number;
+    truncateAnnotation?: string;
+    truncateAnnotationColor?: Formatter;
+}
+
+declare function setupCommonEnv(config: ResolvedConfig): Promise<void>;
+declare function loadDiffConfig(config: ResolvedConfig, executor: VitestExecutor): Promise<DiffOptions | undefined>;
+declare function loadSnapshotSerializers(config: ResolvedConfig, executor: VitestExecutor): Promise<void>;
+
+interface Loader {
+    executeId: (id: string) => Promise<{
+        default: CoverageProviderModule;
+    }>;
+}
+declare function getCoverageProvider(options: CoverageOptions | undefined, loader: Loader): Promise<CoverageProvider | null>;
+declare function startCoverageInsideWorker(options: CoverageOptions | undefined, loader: Loader): Promise<unknown>;
+declare function takeCoverageInsideWorker(options: CoverageOptions | undefined, loader: Loader): Promise<unknown>;
+declare function stopCoverageInsideWorker(options: CoverageOptions | undefined, loader: Loader): Promise<unknown>;
+
+export { getCoverageProvider, loadDiffConfig, loadSnapshotSerializers, setupCommonEnv, startCoverageInsideWorker, stopCoverageInsideWorker, takeCoverageInsideWorker };