fix: add virtual environment setup in Dockerfile

Dockerfile

@@ -20,12 +20,15 @@ COPY templates/ templates/
 # Create uploads directory
 RUN mkdir -p static/uploads
 
-# Install Python dependencies
-RUN uv pip install -e .
+# Create and activate virtual environment, then install dependencies
+RUN uv venv && \
+    . .venv/bin/activate && \
+    uv pip install -e .
 
 # Set environment variables
 ENV FLASK_APP=main.py
 ENV FLASK_ENV=production
+ENV PATH="/app/.venv/bin:$PATH"
 
 # Expose port
 EXPOSE 5000