Add full app source

Adds the Flutter inventory app source, cleaned up for a shared repo:
generic package name, no hardcoded ERP endpoints (moved to gitignored
local config), no dead auth code, no debug logging of session data.

lib/main.dart

@@ -0,0 +1,63 @@
+import 'package:flutter/material.dart';
+import 'package:flutter/services.dart';
+import 'package:get/get.dart';
+import 'package:get_storage/get_storage.dart';
+import 'package:inventory_app/auth.dart';
+import 'package:inventory_app/controllers/theme_controller.dart';
+import 'package:inventory_app/controllers/home_controller.dart';
+
+import 'controllers/user_controller.dart';
+
+void main() async {
+  WidgetsFlutterBinding.ensureInitialized();
+  await GetStorage.init();
+
+  SystemChrome.setEnabledSystemUIMode(SystemUiMode.immersiveSticky);
+  debugDisableShadows = true;
+
+  final themeController = Get.put(ThemeController()); // inject globally
+  Get.lazyPut(() => HomeController());
+  Get.put(UserController()); // Register it ONE TIME globally
+
+  runApp(MyApp(themeController: themeController));
+}
+
+class MyApp extends StatelessWidget {
+  final ThemeController themeController;
+
+  const MyApp({super.key, required this.themeController});
+
+  @override
+  Widget build(BuildContext context) {
+    return GetMaterialApp(
+      debugShowCheckedModeBanner: false,
+      title: 'Inventory App',
+      themeMode: themeController.theme,
+      theme: ThemeData(
+        brightness: Brightness.light,
+        primarySwatch: Colors.blue,
+        scaffoldBackgroundColor: const Color(0xFFF6F8FC),
+        cardColor: Colors.white,
+        appBarTheme: const AppBarTheme(
+          backgroundColor: Colors.white,
+          foregroundColor: Colors.black87,
+          elevation: 0,
+          titleTextStyle: TextStyle(color: Colors.black),
+        ),
+      ),
+      darkTheme: ThemeData(
+        brightness: Brightness.dark,
+        primarySwatch: Colors.blue,
+        scaffoldBackgroundColor: const Color(0xFF121212),
+        cardColor: const Color(0xFF1E1E1E),
+        appBarTheme: const AppBarTheme(
+          backgroundColor: Color(0xFF1E1E1E),
+          foregroundColor: Colors.white,
+          elevation: 0,
+          titleTextStyle: TextStyle(color: Colors.white),
+        ),
+      ),
+      home: const Auth(),
+    );
+  }
+}