Function parse_rndc_secret_data 

pub fn parse_rndc_secret_data(
    data: &BTreeMap<String, Vec<u8>>,
) -> Result<RndcKeyData>

Parse RNDC key data from a Kubernetes Secret.

Supports two Secret formats:

1. Operator-generated (all 4 fields): key-name, algorithm, secret, rndc.key
2. External/user-managed (minimal): rndc.key only - parses the BIND9 key file

Errors

Returns an error if:

• Neither the metadata fields nor rndc.key are present
• The rndc.key file cannot be parsed
• Values are not valid UTF-8 strings