link to current relevant docs on init

Can't hurt (too much) to link to relevant documentation (until the link falls out of date...)

This was an AI-suggested change, for what it's worth.

docker-compose.yml

@@ -21,4 +21,5 @@ services:
       - ./actual-data:/data
     restart: unless-stopped
     # forward signals to Node.js for faster container shutdown
+    # see https://docs.docker.com/reference/compose-file/services/#init
     init: true