A chronic ongoing condition has no end date, so counting it as rest mode
kept the account in it for good: Day N counted from an onset years back,
cadence nudges never resumed and every streak gap since the onset was
bridged. Only active episodes that are not CHRONIC_ONGOING (acute,
recurring, flare) now trigger rest mode, and Day N counts from the
earliest of those. The achievements streak freeze applies the same
filter to its own episode query.
Chronic conditions stay context: a coincident vital deviation is still
framed as explained by any active episode, and the Coach block and the
briefing still name them, with restMode false.
Refs #1216
