Added sigterm handling to exit cleanly when running in Docker.

Fixed typos and various linting issues such as PEP violations.
Added ruff and fixed common issues and linting issues.

docker/dockerfile

@@ -37,7 +37,7 @@ COPY main.py main.py
 COPY src src
 
 
-# Install health check
+# Install health check
 RUN apt-get update && apt-get install -y --no-install-recommends procps && \
     apt-get clean && rm -rf /var/lib/apt/lists/*
 HEALTHCHECK --interval=30s --timeout=5s --start-period=10s --retries=3 \