Use local SSL trust store

[Clete2]

I am using opencode with a LiteLLM proxy that has a SSL cert signed internally by my corporate organization.

When I try to test it, I get an error message: "UnknownError Error: unable to get local issuer certificate"

When I cURL the LiteLLM proxy URL, it works, because the certificate is signed by a trusted signer. Opencode should use my system truststore.

macOS Sequoia 15.6

(PS I also am having #1154 as an issue, which might be related, I am not sure)