Function build_http_client 

pub fn build_http_client(timeout_secs: Option<u64>) -> Result<Client>

Build a configured reqwest::Client with sensible defaults.

Features:

• rustls-tls (no OpenSSL)
• Gzip + Brotli decompression
• Configurable timeout (default: 30s)
• Custom User-Agent

Errors

Returns an error if the HTTP client cannot be built (e.g. TLS init failure).