Fix Dockerfile to copy serve.py instead of server.py

Dockerfile

@@ -18,7 +18,7 @@ COPY requirements.txt .
 RUN pip install --no-cache-dir -r requirements.txt
 
 # Copy application files
-COPY server.py .
+COPY serve.py .
 
 # Expose the port that HF Spaces expects
 EXPOSE 7860