GLM-5.x coding-plan SKUs idle for minutes mid-reasoning, so they get a
600s stream idle-timeout floor instead of the 120s default. That floor
was gated to the native Z.AI/Zhipu hosts only, so GLM-5.2 served through
the OpenCode Go/Zen gateways fell back to the 120s watchdog and stalled
with "OpenAI completions stream stalled while waiting for the next event"
during the slow /plan writing phase.
Fixes#4758
roboomp
7cdecd824a