Function curl_binary_path 

pub fn curl_binary_path() -> &'static str

What: Resolved curl executable path for subprocess or shell wrappers (e.g. privileged fetch).

Inputs:

• None.

Output:

• Path string matching the same resolution used by curl helpers (absolute binary when found).

Details:

• Prefer this over hard-coding curl so planners can probe --version and build argv-safe commands.