When you tried caddy and received an error, that looks like you are getting the wrong image name.
Then you mentioned deleting caddyfile as the configuration didn’t work. But, if I am following correctly the caddyfile wouldn’t yet be relevant if the caddy container hadn’t actually ran.
Pulling from Caddys docs, you should just need to run
I personally found IRC to be the best solution for ebooks. Not sure how much detail/links are allowed here but theres plenty of guides. Look for “IRCHighway ebooks” on your preferred search engine
I wouldn’t agree with that. Whats stopping the other user screenshotting it? Taking a photo with another device? Or even simply disconnecting from the network so the device can’t even receive the “kill switch command”?