docs(cyclones): document the early-advisory window and pin its bounds

Maintainer follow-up for #741, no runtime change.

- CURRENT-STATE: advisory issue and position times up to and including
  90 minutes ahead of the server clock are accepted because NHC can release
  advisories before their nominal time; 90 minutes is the app's tolerance,
  not an NHC limit. Later, non-canonical and over-12-hour-old times still
  reject the snapshot.
- Tests: pin exact 90-minute acceptance and +1 ms rejection, and exact
  12-hour acceptance and +1 ms rejection, for issuance and lastUpdate
  independently; the early-publication test now asserts
  invalid_cyclone_data.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

docs/CURRENT-STATE.md

@@ -339,7 +339,12 @@ Cyclones combine fixed NHC/CPHC status and summary GIS endpoints through a bound
 same-origin provider. The status endpoint lacks browser CORS; each installation
 fetches keyless public sources at runtime, with no centralized ingestion service.
 The five-minute snapshot covers Atlantic and eastern/central North Pacific only.
-Current positions, advisory issue time and position time stay distinct. Tracks,
+Current positions, advisory issue time and position time stay distinct. NHC may
+release an advisory before its nominal time (routinely up to about 30 minutes,
+rarely about an hour), so advisory issue and position times up to and including
+90 minutes ahead of the server clock are accepted; 90 minutes is this app's
+tolerance, not an NHC limit. Later, non-canonical, or more than 12-hour-old
+times still reject the status snapshot. Tracks,
 forecast lead-hour points and cones render only when all source parts match the
 status advisory; a newer status shows its position with geometry pending rather
 than relabeling older geometry. The cone represents forecast center uncertainty,