Each started context had two host threads, polling every 10 ms of wall
time: one sent queued packets, received, and ran hellos, keepalives and
timeouts, and the other handed events to the callbacks. A single
CoreTiming event now does both for every running context, every 1 ms of
emulated time, and Stop does what the threads did on their way out.
Matching no longer depends on host scheduling or wall-clock delays, so an
accept's ESTABLISHED comes 1-10 ms after SelectTarget at any emulation
speed, as on a PSP (pspautotests net/adhoc/pair/matchingaccept).
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
