fix(opencode): default chunk timeout to five minutes

[rekram1-node]

Sets the default timeout between streamed SSE response chunks to five minutes (300,000 ms). Stalled requests are aborted and retried using the existing retry policy. This limits inactivity between chunks, not the total response duration.

To disable it for a provider, set chunkTimeout to false in your project's opencode.json or global ~/.config/opencode/opencode.json:

{
  "provider": {
    "anthropic": {
      "options": {
        "chunkTimeout": false
      }
    }
  }
}

Replace anthropic with your provider. To change the timeout instead, use a positive number of milliseconds, such as "chunkTimeout": 600000 for ten minutes. Omit the setting to use the five-minute default.