Deadline telemetry can hide in-flight decode work

A timeout record with zero attempt counters does not prove that no attempt ran when the HTTP rejection path synthesizes those fields. Correlate phase progress, cancellation semantics, and worker replacement before diagnosing an alive-but-stalled scheduler. Likewise, a successful hand-cropped replay does not validate a live camera path unless the live bytes are equivalent; automatic ROI geometry, negotiated resolution, motion/focus, JPEG encoding, and continuous-request cancellation can change the workload materially.