feat: MeshCore SAR - Flutter BLE mesh radio companion app

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

lib/services/build_info_service.dart

@@ -0,0 +1,54 @@
+import 'dart:io' show Platform;
+import 'package:flutter/services.dart';
+import 'package:flutter/foundation.dart';
+
+/// Service for accessing build information from native platform code
+/// Currently supports Android only - returns "unknown" for other platforms
+class BuildInfoService {
+  static final BuildInfoService _instance = BuildInfoService._internal();
+  factory BuildInfoService() => _instance;
+  BuildInfoService._internal();
+
+  static const MethodChannel _channel = MethodChannel('com.meshcore.sar/build_info');
+
+  String? _cachedCommitHash;
+
+  /// Get the commit hash that was embedded during build time
+  /// Returns "unknown" if:
+  /// - Not running on Android
+  /// - Platform channel call fails
+  /// - Build was not configured with COMMIT_HASH
+  Future<String> getCommitHash() async {
+    // Return cached value if available
+    if (_cachedCommitHash != null) {
+      return _cachedCommitHash!;
+    }
+
+    // Only Android has the platform channel implementation
+    if (!Platform.isAndroid) {
+      debugPrint('[BuildInfoService] Not on Android platform, returning "unknown"');
+      _cachedCommitHash = 'unknown';
+      return _cachedCommitHash!;
+    }
+
+    try {
+      final String commitHash = await _channel.invokeMethod('getCommitHash');
+      _cachedCommitHash = commitHash;
+      debugPrint('[BuildInfoService] Commit hash: $commitHash');
+      return commitHash;
+    } on PlatformException catch (e) {
+      debugPrint('[BuildInfoService] Failed to get commit hash: ${e.message}');
+      _cachedCommitHash = 'unknown';
+      return _cachedCommitHash!;
+    } catch (e) {
+      debugPrint('[BuildInfoService] Unexpected error getting commit hash: $e');
+      _cachedCommitHash = 'unknown';
+      return _cachedCommitHash!;
+    }
+  }
+
+  /// Clear cached commit hash (useful for testing)
+  void clearCache() {
+    _cachedCommitHash = null;
+  }
+}