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/intrinsic.js

@@ -0,0 +1,61 @@
+let OldValue = require('../old-value')
+let Value = require('../value')
+
+function regexp(name) {
+  return new RegExp(`(^|[\\s,(])(${name}($|[\\s),]))`, 'gi')
+}
+
+class Intrinsic extends Value {
+  add(decl, prefix) {
+    if (decl.prop.includes('grid') && prefix !== '-webkit-') {
+      return undefined
+    }
+    return super.add(decl, prefix)
+  }
+
+  isStretch() {
+    return (
+      this.name === 'stretch' ||
+      this.name === 'fill' ||
+      this.name === 'fill-available'
+    )
+  }
+
+  old(prefix) {
+    let prefixed = prefix + this.name
+    if (this.isStretch()) {
+      if (prefix === '-moz-') {
+        prefixed = '-moz-available'
+      } else if (prefix === '-webkit-') {
+        prefixed = '-webkit-fill-available'
+      }
+    }
+    return new OldValue(this.name, prefixed, prefixed, regexp(prefixed))
+  }
+
+  regexp() {
+    if (!this.regexpCache) this.regexpCache = regexp(this.name)
+    return this.regexpCache
+  }
+
+  replace(string, prefix) {
+    if (prefix === '-moz-' && this.isStretch()) {
+      return string.replace(this.regexp(), '$1-moz-available$3')
+    }
+    if (prefix === '-webkit-' && this.isStretch()) {
+      return string.replace(this.regexp(), '$1-webkit-fill-available$3')
+    }
+    return super.replace(string, prefix)
+  }
+}
+
+Intrinsic.names = [
+  'max-content',
+  'min-content',
+  'fit-content',
+  'fill',
+  'fill-available',
+  'stretch'
+]
+
+module.exports = Intrinsic