feat: Add healthcheck CMD to Docker image

Author: BYK

Dockerfile

@@ -3,4 +3,6 @@ ARG TARGETARCH
 WORKDIR /app
 COPY --chmod=555 packages/spotlight/dist-bin/spotlight-linux-$TARGETARCH /app/spotlight
 
+HEALTHCHECK CMD [ "bash", "-c", "exec 3<>'/dev/tcp/localhost/8969' && printf 'GET /health HTTP/1.0\r\nHost: localhost\r\n\r\n' >&3 && read -r line <&3 && echo \"$line\" | grep -q '200 OK'" ]
+
 ENTRYPOINT ["/app/spotlight"]