Phase 3 completed: Flutter MVP with live streaming and auto-refresh

frontend/lib/pages/register_page.dart

@@ -0,0 +1,59 @@
+import 'dart:convert';
+import 'package:flutter/material.dart';
+import 'package:provider/provider.dart';
+import '../providers/settings_provider.dart';
+import '../services/api_service.dart';
+
+class RegisterPage extends StatefulWidget {
+  @override
+  _RegisterPageState createState() => _RegisterPageState();
+}
+
+class _RegisterPageState extends State<RegisterPage> {
+  final _usernameController = TextEditingController();
+  final _passwordController = TextEditingController();
+  bool _isLoading = false;
+
+  void _handleRegister() async {
+    setState(() => _isLoading = true);
+    final settings = context.read<SettingsProvider>();
+    final api = ApiService(settings, null);
+
+    try {
+      final response = await api.register(
+        _usernameController.text,
+        _passwordController.text,
+      );
+
+      if (response.statusCode == 201) {
+        ScaffoldMessenger.of(context).showSnackBar(SnackBar(content: Text("Registered! Please login.")));
+        Navigator.pop(context);
+      } else {
+        final error = jsonDecode(response.body)['error'] ?? "Registration Failed";
+        ScaffoldMessenger.of(context).showSnackBar(SnackBar(content: Text(error)));
+      }
+    } catch (e) {
+      ScaffoldMessenger.of(context).showSnackBar(SnackBar(content: Text("Network Error")));
+    } finally {
+      setState(() => _isLoading = false);
+    }
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return Scaffold(
+      appBar: AppBar(title: Text("Register")),
+      body: Padding(
+        padding: const EdgeInsets.all(16.0),
+        child: Column(
+          children: [
+            TextField(controller: _usernameController, decoration: InputDecoration(labelText: "Username")),
+            TextField(controller: _passwordController, decoration: InputDecoration(labelText: "Password"), obscureText: true),
+            SizedBox(height: 20),
+            _isLoading ? CircularProgressIndicator() : ElevatedButton(onPressed: _handleRegister, child: Text("Register")),
+          ],
+        ),
+      ),
+    );
+  }
+}