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/loose-envify/README.md

@@ -0,0 +1,45 @@
+# loose-envify
+
+[![Build Status](https://travis-ci.org/zertosh/loose-envify.svg?branch=master)](https://travis-ci.org/zertosh/loose-envify)
+
+Fast (and loose) selective `process.env` replacer using [js-tokens](https://github.com/lydell/js-tokens) instead of an AST. Works just like [envify](https://github.com/hughsk/envify) but much faster.
+
+## Gotchas
+
+* Doesn't handle broken syntax.
+* Doesn't look inside embedded expressions in template strings.
+  - **this won't work:**
+  ```js
+  console.log(`the current env is ${process.env.NODE_ENV}`);
+  ```
+* Doesn't replace oddly-spaced or oddly-commented expressions.
+  - **this won't work:**
+  ```js
+  console.log(process./*won't*/env./*work*/NODE_ENV);
+  ```
+
+## Usage/Options
+
+loose-envify has the exact same interface as [envify](https://github.com/hughsk/envify), including the CLI.
+
+## Benchmark
+
+```
+envify:
+
+  $ for i in {1..5}; do node bench/bench.js 'envify'; done
+  708ms
+  727ms
+  791ms
+  719ms
+  720ms
+
+loose-envify:
+
+  $ for i in {1..5}; do node bench/bench.js '../'; done
+  51ms
+  52ms
+  52ms
+  52ms
+  52ms
+```