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/autoprefixer/lib/hacks/text-emphasis-position.js

@@ -0,0 +1,14 @@
+let Declaration = require('../declaration')
+
+class TextEmphasisPosition extends Declaration {
+  set(decl, prefix) {
+    if (prefix === '-webkit-') {
+      decl.value = decl.value.replace(/\s*(right|left)\s*/i, '')
+    }
+    return super.set(decl, prefix)
+  }
+}
+
+TextEmphasisPosition.names = ['text-emphasis-position']
+
+module.exports = TextEmphasisPosition