W-011: recognition refusal_reason now materializes in
CognitiveTurnResult.refusal_reason via RECOGNITION_REFUSED enum value.
Precedence: recognition wins over generation (earlier-fail boundary).
W-012: ChatRuntime.chat() catches InnerLoopExhaustion from generate()
and returns a typed refusal ChatResponse with refusal_reason populated,
instead of propagating as an unhandled exception.
Adds RefusalReason.RECOGNITION_REFUSED to generate/exhaustion.py.
Lane SHAs: 7/7 match (demos don't exercise refusal paths — no re-pin).
Smoke + cognition suites green. Full suite not run to completion.
