The "Updating propagation +Nh" chip was double-misleading in prod:
the label's +Nh was relative to the HRRR run time (which lags wall
clock by ~2h), and the progress broadcast fired before the hour was
fetched + persisted — so the chip could read "+8h" while the map
timeline only extended to +4h.
Reframe the label as "through now" / "through +Nh" / "through Nh ago"
by computing the offset from valid_time → now in PipelineStatus.
running_detail, so it matches the semantic the user reads off the
timeline. Move the PubSub broadcast in PropagationGridWorker to fire
after Propagation.replace_scores/2 succeeds, so the chip only
advances once that forecast hour is readable from ScoresFile.
Graham McIntire
11617e730b