Built-in OpenAI-compatible provider managers call fetchOpenAICompatibleModels with neither a signal nor a timeoutMs, and the no-timeout branch issued the request with signal: undefined. A stalled /models endpoint left the fetch pending forever, so createAgentSession's awaited resolveModelDiscoveryFallback discovery pass never returned and startup hung.
Apply a default 10s deadline (DEFAULT_OPENAI_COMPATIBLE_DISCOVERY_TIMEOUT_MS) when the caller supplies neither signal nor timeoutMs, matching the coding-agent remote-discovery budget. Callers passing their own signal keep owning its lifecycle.
Fixes#8315
roboomp
100d2ef547