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/lines-and-columns/build/index.d.ts

@@ -0,0 +1,13 @@
+export declare type SourceLocation = {
+    line: number;
+    column: number;
+};
+export declare class LinesAndColumns {
+    private string;
+    private offsets;
+    constructor(string: string);
+    locationForIndex(index: number): SourceLocation | null;
+    indexForLocation(location: SourceLocation): number | null;
+    private lengthOfLine;
+}
+export default LinesAndColumns;