* feat: 1Password Connect secret sources for SSH credentials
Hosts and credentials can hold op://vault/item/field references instead
of secrets; they are resolved at connect time from the user's secret
source (1Password Connect) at the single point where every subsystem
receives plaintext credentials, so terminal, SFTP, Docker, metrics and
tunnels all work without per-subsystem changes. Sources are per user,
optionally shared, with the access token encrypted under the owner's
data key; resolved values are cached briefly in memory.
* style: format secret source changes
