Decode deadlines are not decoder outcomes

When a realtime decode request expires, classify the observation at the boundary that actually completed. A request deadline is not the same as a decoder no-read, parse failure, or completed fallback. Correlate durable route selection, the last completed engine phase, and proxy completion evidence before assigning the failure to routing, transport, queueing, or decoding.

Applicability: asynchronous, hedged, or multi-stage decode pipelines with an outer request deadline. Limits: a phase label can narrow where time was spent, but without per-attempt queue, start, cancellation, and drain telemetry it cannot prove worker starvation or a native deadlock. Retry counts should be reduced to affected flows and eventual recovery rather than treated as independent failures.

Evidence basis (2026-09-22): source review of the cited decoder path supports the distinction between an outer deadline and a completed decoder result. The original production cohort, exact timings, and route counts were not independently recovered and are intentionally omitted.