Phase 2: Performance Profiling Setup - Add profiling utilities

- Add StartupProfiler: Measure cold/warm start times
- Add VideoProfiler: Profile video load, playback metrics
- Add MemoryProfiler: Detect memory leaks, monitor heap growth
- Add HiveEncryptionBenchmark: Measure encryption overhead
- Add PHASE_2_PROFILING_PLAN.md: Complete testing procedures

Ready for profiling execution once Flutter SDK is initialized

lib/core/utils/video_profiler.dart

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+import 'dart:async';
+import 'package:flutter/foundation.dart';
+
+/// Profiler for video playback performance metrics
+class VideoProfiler {
+  static final metrics = <String, VideoMetrics>{};
+
+  /// Start profiling a video stream
+  static void startStreamMetrics(String streamName) {
+    metrics[streamName] = VideoMetrics(
+      streamName: streamName,
+      startTime: DateTime.now(),
+      loadStart: DateTime.now(),
+    );
+    if (kDebugMode) {
+      print('📺 START PROFILING: $streamName');
+    }
+  }
+
+  /// Mark when video is ready to play
+  static void markLoadComplete(String streamName) {
+    final m = metrics[streamName];
+    if (m != null) {
+      m.loadTime = DateTime.now().difference(m.loadStart).inMilliseconds;
+      if (kDebugMode) {
+        print('✅ VIDEO LOADED: ${m.loadTime}ms');
+      }
+    }
+  }
+
+  /// Mark first frame rendered
+  static void markFirstFrame(String streamName) {
+    final m = metrics[streamName];
+    if (m != null) {
+      m.firstFrameTime =
+          DateTime.now().difference(m.loadStart).inMilliseconds;
+      if (kDebugMode) {
+        print('🎬 FIRST FRAME: ${m.firstFrameTime}ms');
+      }
+    }
+  }
+
+  /// Record peak memory usage during playback
+  static void recordMemoryPeak(String streamName, int bytes) {
+    final m = metrics[streamName];
+    if (m != null) {
+      m.peakMemoryMB = bytes ~/ (1024 * 1024);
+      if (kDebugMode) {
+        print('💾 PEAK MEMORY: ${m.peakMemoryMB}MB');
+      }
+    }
+  }
+
+  /// Record average CPU usage
+  static void recordCpuUsage(String streamName, double percentage) {
+    final m = metrics[streamName];
+    if (m != null) {
+      m.avgCpuPercent = percentage;
+      if (kDebugMode) {
+        print('⚡ AVG CPU: ${percentage.toStringAsFixed(1)}%');
+      }
+    }
+  }
+
+  /// Mark seek response time
+  static void markSeekResponse(String streamName, int durationMs) {
+    final m = metrics[streamName];
+    if (m != null) {
+      m.seekResponseMs = durationMs;
+      if (kDebugMode) {
+        print('🔄 SEEK RESPONSE: ${durationMs}ms');
+      }
+    }
+  }
+
+  /// End profiling session
+  static void endSession(String streamName) {
+    final m = metrics[streamName];
+    if (m != null) {
+      m.endTime = DateTime.now();
+      m.totalDurationMs =
+          m.endTime!.difference(m.startTime).inMilliseconds;
+      if (kDebugMode) {
+        print('\n' + ('=' * 50));
+        print('📊 VIDEO METRICS: $streamName');
+        print('=' * 50);
+        m.printMetrics();
+        print('=' * 50 + '\n');
+      }
+    }
+  }
+
+  /// Get summary of all metrics
+  static void printSummary() {
+    if (kDebugMode) {
+      print('\n' + ('=' * 50));
+      print('📈 VIDEO PROFILING SUMMARY');
+      print('=' * 50);
+      metrics.forEach((key, m) {
+        print('\n$key:');
+        m.printMetrics();
+      });
+      print('=' * 50 + '\n');
+    }
+  }
+
+  /// Export metrics as JSON
+  static Map<String, dynamic> toJson() {
+    return {
+      'timestamp': DateTime.now().toIso8601String(),
+      'metrics': {
+        for (var e in metrics.entries) e.key: e.value.toJson(),
+      },
+    };
+  }
+
+  /// Reset all metrics
+  static void reset() {
+    metrics.clear();
+  }
+}
+
+/// Container for video stream metrics
+class VideoMetrics {
+  final String streamName;
+  final DateTime startTime;
+  final DateTime loadStart;
+
+  int? loadTime; // ms
+  int? firstFrameTime; // ms
+  int? peakMemoryMB;
+  double? avgCpuPercent;
+  int? seekResponseMs;
+  DateTime? endTime;
+  int? totalDurationMs;
+
+  VideoMetrics({
+    required this.streamName,
+    required this.startTime,
+    required this.loadStart,
+  });
+
+  void printMetrics() {
+    print('  Load Time: ${loadTime ?? "N/A"}ms');
+    print('  First Frame: ${firstFrameTime ?? "N/A"}ms');
+    print('  Peak Memory: ${peakMemoryMB ?? "N/A"}MB');
+    print('  Avg CPU: ${avgCpuPercent?.toStringAsFixed(1) ?? "N/A"}%');
+    print('  Seek Response: ${seekResponseMs ?? "N/A"}ms');
+    print('  Total Duration: ${totalDurationMs ?? "N/A"}ms');
+  }
+
+  Map<String, dynamic> toJson() {
+    return {
+      'streamName': streamName,
+      'loadTime': loadTime,
+      'firstFrameTime': firstFrameTime,
+      'peakMemoryMB': peakMemoryMB,
+      'avgCpuPercent': avgCpuPercent,
+      'seekResponseMs': seekResponseMs,
+      'totalDurationMs': totalDurationMs,
+    };
+  }
+}