Function export_hosts_to_json 

pub fn export_hosts_to_json(
    hosts: &BTreeMap<String, VpsRecord>,
    include_secrets: bool,
) -> BTreeMap<String, ExportHostJson>

GAP-SSH-UX-001: hosts for vps export --json.

• Redacted (include_secrets=false): empty secrets / null optional, never ciphertext sshcli-enc: (EXP-001 parity). Empty password → "" skeleton.
• With secrets: plaintext only if --include-secrets (same risk as TOML).