feat: initial implementation of People Counter web app

- Add Flask application with MJPEG video streaming
- Implement OpenCV DNN face detection module
- Add zone-based entry/exit tracking with cooldown mechanism
- Create web interface with real-time WebSocket updates
- Add model download script and comprehensive README
- Include OpenCV DNN model files for face detection

app.py

@@ -0,0 +1,118 @@
+"""
+Flask Application for People Counter Web App
+Provides video streaming and real-time count updates via WebSocket.
+"""
+
+from flask import Flask, render_template, Response
+from flask_socketio import SocketIO, emit
+import time
+import threading
+from camera import Camera
+
+app = Flask(__name__)
+app.config['SECRET_KEY'] = 'people-counter-secret-key'
+socketio = SocketIO(app, cors_allowed_origins="*")
+
+# Global camera instance
+camera = None
+count_update_interval = 0.5  # Update counts every 0.5 seconds
+
+
+def initialize_camera():
+    """Initialize the camera."""
+    global camera
+    try:
+        camera = Camera(camera_index=0, process_every_n_frames=3)
+        camera.start()
+        print("Camera initialized successfully")
+        return True
+    except Exception as e:
+        print(f"Failed to initialize camera: {e}")
+        return False
+
+
+def count_update_thread():
+    """Background thread to periodically send count updates via WebSocket."""
+    while True:
+        time.sleep(count_update_interval)
+        if camera:
+            counts = camera.get_counts()
+            socketio.emit('count_update', counts)
+        else:
+            # Send zero counts if camera not available
+            socketio.emit('count_update', {
+                'total_entered': 0,
+                'total_exited': 0,
+                'current_occupancy': 0
+            })
+
+
+@app.route('/')
+def index():
+    """Serve the main page."""
+    return render_template('index.html')
+
+
+def generate_frames():
+    """Generator function for MJPEG video streaming."""
+    while True:
+        if camera:
+            frame = camera.get_frame()
+            if frame:
+                yield (b'--frame\r\n'
+                       b'Content-Type: image/jpeg\r\n\r\n' + frame + b'\r\n')
+            else:
+                time.sleep(0.1)
+        else:
+            time.sleep(0.1)
+
+
+@app.route('/video_feed')
+def video_feed():
+    """Video streaming route."""
+    return Response(generate_frames(),
+                    mimetype='multipart/x-mixed-replace; boundary=frame')
+
+
+@socketio.on('connect')
+def handle_connect():
+    """Handle WebSocket connection."""
+    print('Client connected')
+    if camera:
+        counts = camera.get_counts()
+        emit('count_update', counts)
+
+
+@socketio.on('disconnect')
+def handle_disconnect():
+    """Handle WebSocket disconnection."""
+    print('Client disconnected')
+
+
+@socketio.on('reset_counts')
+def handle_reset_counts():
+    """Handle reset counts request."""
+    if camera:
+        camera.reset_counts()
+        counts = camera.get_counts()
+        emit('count_update', counts)
+        emit('reset_confirmation', {'status': 'success'})
+
+
+if __name__ == '__main__':
+    # Initialize camera
+    if initialize_camera():
+        # Start background thread for count updates
+        update_thread = threading.Thread(target=count_update_thread, daemon=True)
+        update_thread.start()
+        
+        # Run Flask app
+        try:
+            socketio.run(app, host='0.0.0.0', port=5000, debug=False, allow_unsafe_werkzeug=True)
+        except KeyboardInterrupt:
+            print("\nShutting down...")
+        finally:
+            if camera:
+                camera.stop()
+    else:
+        print("Failed to initialize camera. Exiting.")