Follow-up hardening on the per-model background concurrency governor:
- limiter: heartbeat now refreshes the ZSET key's PEXPIRE alongside the
lease score, so a semaphore that stays saturated with no slot turnover
can't let the whole key expire (which would drop every lease and admit
over the limit); reuse one poll timer instead of allocating time.After
each iteration under contention.
- governor: extract the process-wide governor + Gate helper into the
limiter package so chat and vlm share one limiter/limit without
importing each other; add an in-process localLimiter for Lite mode.
- vlm: gate background multimodal (VLM) calls through the same governor;
previously only chat was throttled.
- chat: ChatStream releases its slot when the consumer abandons the
stream and cancels ctx (select on ctx.Done, drain inner), fixing a
slot/goroutine leak.
- container/sync_task: install the local governor in Lite mode and tag
SyncTaskExecutor runs as background; honour model.max_concurrency=0 as
an explicit disable instead of falling back to the default.
- tests: cover the governor gating, local limiter, and stream release.
wizardchen
98ad41cda4