feat: add frontend app, improve static file serving with lazy loading and root redirect

frontend/lib/main.dart

@@ -0,0 +1,30 @@
+import 'package:flutter/material.dart';
+import 'screens/pipeline_list.dart';
+
+void main() {
+  runApp(const ZaloopipeApp());
+}
+
+class ZaloopipeApp extends StatelessWidget {
+  const ZaloopipeApp({super.key});
+
+  @override
+  Widget build(BuildContext context) {
+    return MaterialApp(
+      title: 'Zaloopipe',
+      debugShowCheckedModeBanner: false,
+      theme: ThemeData(
+        colorSchemeSeed: Colors.blue,
+        useMaterial3: true,
+        brightness: Brightness.light,
+      ),
+      darkTheme: ThemeData(
+        colorSchemeSeed: Colors.blue,
+        useMaterial3: true,
+        brightness: Brightness.dark,
+      ),
+      themeMode: ThemeMode.system,
+      home: const PipelineListScreen(),
+    );
+  }
+}