SSE event subscription ignores custom fetch (Basic Auth broken) #28180

Description

createOpencodeClient({ fetch }) allows passing a custom fetch implementation for authentication (e.g., Basic Auth, Bearer tokens, or custom headers). While the standard API endpoints honor this setting, the SSE client used for events (client.event.subscribe()) was hard-coded to use the global fetch.

This causes SSE connections to fail with 401 Unauthorized errors when the server is protected, leading to a silent reconnection loop.

OpenCode version

1.14.41

Steps to reproduce

1. Start an OpenCode server behind Basic Auth.
2. Initialize the client with a custom fetch:

   const client = createOpencodeClient({
     baseUrl: "...",
     fetch: (req) => {
       const headers = new Headers(req.headers);
       headers.set("Authorization", "Basic ...");
       return globalThis.fetch(new Request(req, { headers }));
     }
   });

3. Call client.session.list() (works).
4. Call client.event.subscribe() (fails with 401, retries forever).

Screenshot and/or share link

N/A

Operating System

macOS / Linux

Terminal

zsh / bash