Add build-essential to Dockerfile for webrtcvad compilation

Dockerfile

@@ -1,7 +1,8 @@
 FROM python:3.10-slim
 
-# Install system dependencies
+# Install system dependencies including build tools for webrtcvad
 RUN apt-get update && apt-get install -y \
+    build-essential \
     libsndfile1 libsndfile1-dev \
     ffmpeg \
     git \