fix deploy-rs: use SSH port 2299 and user steffen instead of root

deploy-rs was configured with default port 22 and user root, but
SSH runs on port 2299 and root login is disabled. Also fix ssh-keyscan
in the deploy workflow to use the correct port.

.forgejo/workflows/deploy.yml

@@ -29,7 +29,7 @@ jobs:
           mkdir -p ~/.ssh
           echo "$DEPLOY_KEY" > ~/.ssh/id_ed25519
           chmod 600 ~/.ssh/id_ed25519
-          ssh-keyscan -H cryodev.xyz >> ~/.ssh/known_hosts
+          ssh-keyscan -p 2299 -H cryodev.xyz >> ~/.ssh/known_hosts
 
       - name: Deploy with deploy-rs
         run: nix run github:serokell/deploy-rs -- -s .#cryodev-main