feat: Implement Flutter flavors for dev, stage, and prod environments with corresponding configurations and build scripts.

mobile-apps/apps/krow_staff/test/widget_test.dart

@@ -7,13 +7,21 @@
 
 import 'package:flutter/material.dart';
 import 'package:flutter_test/flutter_test.dart';
-
-import 'package:krow_staff/main.dart';
+import 'package:krow_staff/app_config.dart';
+import 'package:krow_staff/my_app.dart';
 
 void main() {
   testWidgets('Counter increments smoke test', (WidgetTester tester) async {
     // Build our app and trigger a frame.
-    await tester.pumpWidget(const MyApp());
+    await tester.pumpWidget(
+      MyApp(
+        config: AppConfig(
+          environment: Environment.dev,
+          appTitle: 'Test App',
+          apiBaseUrl: 'https://test.com',
+        ),
+      ),
+    );
 
     // Verify that our counter starts at 0.
     expect(find.text('0'), findsOneWidget);