feat(rainscatter): classify QSO propagation mechanism from common-volume radar
Adds a per-contact enrichment pipeline that determines whether a QSO was
most likely carried by rain scatter, tropospheric ducting, or ordinary
troposcatter — using IEM n0q composite reflectivity sampled inside the
lens-shaped intersection of 400 km-radius disks around each endpoint.
Pieces:
* Microwaveprop.Propagation.CommonVolume — lens geometry (haversine,
in-CV test, bbox, area).
* contact_common_volume_radar table (1:1 per contact) storing
aggregate dBZ stats inside the CV + radar_status column on contacts.
* Microwaveprop.Workers.CommonVolumeRadarWorker — Oban :radar queue,
fetches the n0q frame at QSO time, iterates pixels inside the CV
bbox, aggregates rain/heavy/core-pixel counts, max/mean dBZ, and
coverage percentage.
* Microwaveprop.Propagation.RainScatterClassifier — rule-based mapper
from (band, distance, radar stats, duct flags) to one of
:likely_rainscatter | :rainscatter_possible | :tropo_duct |
:troposcatter | :unknown.
* ContactWeatherEnqueueWorker learns a :radar enrichment type and
enqueues the CV worker on contact submission; pre-2014 contacts
(outside IEM n0q coverage) are pinned to :unavailable.
* `mix radar_backfill` bulk-enqueues historical contacts with
--year / --limit / --dry-run.
* Contact detail page renders a mechanism badge with supporting
stats (common-volume area, max dBZ, heavy-rain pixel count,
coverage %).
Graham McIntire
33f5d4edbe