dialViaJump fed target.ProxyJump straight into ResolveSSHTarget as a
host alias. That works for `Host prod-jump` entries in ~/.ssh/config
but turns the literal `user@host:port` form into a single hostname
that the kernel resolver chokes on (`lookup kandev@127.0.0.1:23000: no
such host`).
Detect the literal shape inline (`[user@]host[:port]`) and build the
bastion SSHTarget from its parts. Falls back to the alias path when
no @ / : separators are present.
Fixes the proxy-jump.spec.ts bastion flow. While here:
* scanFingerprintInsideNetwork: alpine package is `openssh-client`,
not the (nonexistent) `openssh-keyscan`. Surface install errors
so future failures aren't silent.
* scanFingerprintViaHost: retry on empty output — sshd accepts TCP
before host-key negotiation completes on a cold container.
* startBastionAndTarget: share one keypair across bastion + target
so a single -i auths both hops (matches how OpenSSH ProxyJump
handles per-host identities outside ~/.ssh/config).
* proxy-jump N1: assert any SHA256 fingerprint came back, since the
test no longer pre-discovers a value to compare against.
José Almeida
9fc84efadf