Internal OpenRouter SDK

Introduced an internal OpenRouter Go SDK generated with Speakeasy for use in the Gram server’s chat service.

The SDK handles request deserialization for OpenRouter API interactions, improving type safety and maintainability. This internal SDK is intended to be replaced by a future official OpenRouter SDK when one becomes available.

Features

• OpenRouter Go SDK integration #1329  - Added a Speakeasy-generated Go SDK for OpenRouter API interactions in the chat service. (Author: @disintegrator )