test: investigate extraction container client EPIPE on Node 24.22.1 #357

The extraction formatting, type checks and unit tests pass after #347, and the hardened Compose service starts healthy. The container qualification client then exits with write EPIPE on Node 24.22.1 after generating adversarial documents, before its final success summary.

The same suite passed on the preceding Node 24.16.0 import. The test client sends complete buffers with req.end(bytes) and rejects every ClientRequest error. Please determine which adversarial request produces the failure and whether the server closes before a valid rejection response is consumed. Preserve all protocol, resource-limit and isolation assertions; do not simply ignore EPIPE without validating the response.

A failed-job-only retry is running to distinguish an intermittent write/response race from a reproducible runtime regression. Initial evidence does not establish a production extraction fault.