Historical contacts showed a skew-T log-P diagram that stopped at 700 mb
because HrrrClient and Era5Client only fetched pressure-level data down
to the top of the boundary layer. The chart canvas already ran up to
100 mb, so the trace clipped mid-atmosphere.
Two complementary fixes:
1. Extend @pressure_levels in HrrrClient and Era5Client with
650/600/550/500/450/400/350/300/250/200/150/100 mb so new fetches
cover the full troposphere + lower stratosphere.
2. Prefer the native hybrid-sigma profile for the contact-detail
skew-T when one has been backfilled for the contact's hour. The
native profile already stores all 50 hybrid levels up to ~19 km,
so historical contacts covered by the native backfill get a full
trace without re-hitting S3. A new HrrrNativeProfile.to_skew_t_profile/1
converts the parallel arrays into the %{"pres","tmpc","dwpc","hght"}
list shape the renderer expects, deriving dewpoint from SPFH via the
Magnus inverse. Weather.find_nearest_native_profile/3 mirrors
find_nearest_hrrr/3 for the lookup.