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/css-tree/lib/index.js

@@ -0,0 +1,30 @@
+import syntax from './syntax/index.js';
+
+export * from './version.js';
+export { default as createSyntax } from './syntax/create.js';
+export { List } from './utils/List.js';
+export { Lexer } from './lexer/Lexer.js';
+export { tokenTypes, tokenNames, TokenStream } from './tokenizer/index.js';
+export * as definitionSyntax from './definition-syntax/index.js';
+export { clone } from './utils/clone.js';
+export * from './utils/names.js';
+export * as ident from './utils/ident.js';
+export * as string from './utils/string.js';
+export * as url from './utils/url.js';
+export const {
+    tokenize,
+    parse,
+    generate,
+    lexer,
+    createLexer,
+
+    walk,
+    find,
+    findLast,
+    findAll,
+
+    toPlainObject,
+    fromPlainObject,
+
+    fork
+} = syntax;