fix(server): sanitize sshd config values in security audit JSON output

Duplicate directives in sshd_config (e.g. two active PermitRootLogin
lines from Match blocks or provisioning scripts) made the grep|awk
captures multi-line. The embedded newline ended up inside a JSON string
literal, so JSON.parse failed with "Bad control character in string
literal" and the Security tab showed a red banner plus default values.

Take the first match (mirroring sshd's first-match-wins semantics) and
strip carriage returns from CRLF-edited configs.