ssh keys usage reminder (simplest home case)

* ssh key setup
** generate
example for github:
ssh-keygen -t ed25519 -C "your_email@example.com"
** client .ssh/config (private key per host)
Host deck
IdentityFile /home/user/.ssh/mydeck
Host github.com
IdentityFile /home/user/.ssh/mygithub
** remote host (server): .ssh/authorized_keys
Copy .pub key contents there.