The gitea-runner is a systemd DynamicUser whose passwd home is /, so ssh
expands ~ to /.ssh/... (not $HOME). deploy-rs passes ssh opts to ssh with
no shell, so a tilde in deploy.nix sshOpts resolved to a missing key and
nix copy failed with 'failed to start SSH connection'.
Keep deploy.nix sshOpts path-free; build absolute -i/known_hosts paths in
deploy.yml from $HOME (bash-expanded) and append them via --ssh-opts, which
deploy-rs merges into NIX_SSHOPTS for the copy and the activation ssh.
Also removes the temporary SSH debug step.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Lars Nolden
5e2454f622