dsh-fetch-timeouts: Increase HTTP Timeout Settings for DeepSeek Harness

The `dsh-fetch-timeouts` plugin is designed to address connection interruptions in DeepSeek Harness (DSH) during local model inference caused by Node.js's default 5-minute timeout mechanism. By raising Node.js's global HTTP timeout threshold to 30 minutes, it allows requests involving prolonged periods without a response or data transfer (such as large file generation) to complete successfully. After installation, `headersTimeoutMs` and `bodyTimeoutMs` must be configured, and watchdogs must be set in provider routes accordingly. The plugin takes effect globally and affects all operations using Node's global fetch, so it should be evaluated carefully.