a bunch of flutter updates

walkguide-mobile/walkguide_app/lib/core/ai/detection_export.dart

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+export 'obstacle_analyzer.dart';
+export 'yolo_detector.dart';

walkguide-mobile/walkguide_app/lib/core/ai/obstacle_analyzer.dart

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+enum ObstacleDirection { left, center, right }
+
+class DetectionResult {
+  final String label;
+  final double confidence;
+  final ObstacleDirection direction;
+  final String estimatedDistance;
+
+  const DetectionResult({
+    required this.label,
+    required this.confidence,
+    required this.direction,
+    required this.estimatedDistance,
+  });
+
+  String get directionName => direction.name.toUpperCase();
+
+  String get spokenId {
+    final area = switch (direction) {
+      ObstacleDirection.left => 'kiri',
+      ObstacleDirection.center => 'tengah',
+      ObstacleDirection.right => 'kanan',
+    };
+    return 'Hati-hati, $label di $area. Jarak $estimatedDistance.';
+  }
+}
+
+class ObstacleAnalyzer {
+  DetectionResult analyzeFallback({String label = 'person', double confidence = 0.86}) {
+    return DetectionResult(
+      label: label,
+      confidence: confidence,
+      direction: ObstacleDirection.center,
+      estimatedDistance: 'Close',
+    );
+  }
+}

walkguide-mobile/walkguide_app/lib/core/ai/yolo_detector.dart

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+import 'package:flutter/foundation.dart';
+import 'package:flutter/services.dart';
+
+import '../constants/app_constants.dart';
+import 'obstacle_analyzer.dart';
+
+class YoloDetector {
+  final ObstacleAnalyzer _analyzer;
+  List<String> _labels = const [];
+  bool _ready = false;
+
+  YoloDetector(this._analyzer);
+
+  bool get isReady => _ready;
+
+  Future<void> init() async {
+    try {
+      _labels = (await rootBundle.loadString(AppConstants.yoloLabelsPath))
+          .split('\n')
+          .map((e) => e.trim())
+          .where((e) => e.isNotEmpty)
+          .toList();
+      if (kIsWeb) {
+        _ready = false;
+        return;
+      }
+      await rootBundle.load(await AppConstants.getSelectedYoloModelPath());
+      _ready = true;
+    } catch (e) {
+      debugPrint('YOLO fallback mode: $e');
+      _ready = false;
+    }
+  }
+
+  Future<DetectionResult?> detectFallback() async {
+    if (_ready) {
+      // Full tensor pre/post-processing belongs here once yolov8n.tflite is present.
+      // The app keeps a deterministic fallback so demo flows remain testable.
+    }
+    final label = _labels.isNotEmpty ? _labels.first : 'person';
+    return _analyzer.analyzeFallback(label: label);
+  }
+
+  void dispose() {
+    _ready = false;
+  }
+}