Initial commit: MeshCore Open Flutter client

Open-source Flutter client for MeshCore LoRa mesh networking devices.

Features:
- BLE device scanning and connection
- Nordic UART Service (NUS) integration
- Material 3 design with system theme support
- Provider-based state management
- Placeholder screens for chat, contacts, and settings

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

lib/widgets/device_tile.dart

@@ -0,0 +1,68 @@
+import 'package:flutter/material.dart';
+import 'package:flutter_blue_plus/flutter_blue_plus.dart';
+
+/// A reusable tile widget for displaying a MeshCore device in a list
+class DeviceTile extends StatelessWidget {
+  final ScanResult scanResult;
+  final VoidCallback onTap;
+
+  const DeviceTile({
+    super.key,
+    required this.scanResult,
+    required this.onTap,
+  });
+
+  @override
+  Widget build(BuildContext context) {
+    final device = scanResult.device;
+    final rssi = scanResult.rssi;
+    final name = device.platformName.isNotEmpty 
+        ? device.platformName 
+        : scanResult.advertisementData.advName;
+
+    return ListTile(
+      leading: _buildSignalIcon(rssi),
+      title: Text(
+        name.isNotEmpty ? name : 'Unknown Device',
+        style: const TextStyle(fontWeight: FontWeight.w500),
+      ),
+      subtitle: Text(device.remoteId.toString()),
+      trailing: ElevatedButton(
+        onPressed: onTap,
+        child: const Text('Connect'),
+      ),
+      onTap: onTap,
+    );
+  }
+
+  Widget _buildSignalIcon(int rssi) {
+    IconData icon;
+    Color color;
+
+    if (rssi >= -60) {
+      icon = Icons.signal_cellular_4_bar;
+      color = Colors.green;
+    } else if (rssi >= -70) {
+      icon = Icons.signal_cellular_alt;
+      color = Colors.lightGreen;
+    } else if (rssi >= -80) {
+      icon = Icons.signal_cellular_alt_2_bar;
+      color = Colors.orange;
+    } else {
+      icon = Icons.signal_cellular_alt_1_bar;
+      color = Colors.red;
+    }
+
+    return Column(
+      mainAxisAlignment: MainAxisAlignment.center,
+      children: [
+        Icon(icon, color: color),
+        Text(
+          '$rssi dBm',
+          style: TextStyle(fontSize: 10, color: color),
+        ),
+      ],
+    );
+  }
+}
+