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/views/splash_screen.dart

@@ -0,0 +1,25 @@
+import 'package:flutter/material.dart';
+import 'package:lottie/lottie.dart';
+
+class SplashScreen extends StatelessWidget {
+  const SplashScreen({super.key});
+
+  @override
+  Widget build(BuildContext context) {
+    final size = MediaQuery.of(context).size;
+    return Scaffold(
+      body: SizedBox(
+        width: size.width,
+        height: size.height,
+        child: Center(
+          child: Lottie.asset(
+            'assets/wave.json',
+            width: size.width,
+            height: size.height,
+            fit: BoxFit.fitWidth,
+          ),
+        ),
+      ),
+    );
+  }
+}