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/confbox/dist/toml.d.ts

@@ -0,0 +1,22 @@
+/**
+ * Converts a [TOML](https://toml.io/) string into an object.
+ *
+ * @NOTE Comments and indentation is not preserved after parsing.
+ *
+ * @template T The type of the return value.
+ * @param text The TOML string to parse.
+ * @returns The JavaScript value converted from the TOML string.
+ */
+declare function parseTOML<T = unknown>(text: string): T;
+/**
+ * Converts a JavaScript value to a [TOML](https://toml.io/) string.
+ *
+ * @NOTE Comments and indentation is not preserved in the output.
+ *
+ * @param value
+ * @param options
+ * @returns The YAML string converted from the JavaScript value.
+ */
+declare function stringifyTOML(value: any): string;
+
+export { parseTOML, stringifyTOML };