Client: cpp
When accept() failed with EMFILE, TServerFramework::serve() stopped for good.
acceptImpl() now waits out running out of descriptors or memory, backing off
from 5 ms to 1 s and staying interruptible, and goes back to poll() when the
error belongs to the one connection. Linux keeps that connection queued, so
retrying without the wait would spin. Neither case is logged per attempt,
because a peer can cause both.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Client: Test (C++)
Patch: John Sirois
Instead of using a fixed port, use an ephemeral port to improve
robustness and make way for parallelizability.
This closes#855
