Classifies every contact's likely non-LOS propagation mechanism and
persists the result on contacts.propagation_mechanism. Mechanism is
determined in priority order:
1. user_declared_prop_mode (ADIF PROP_MODE from the operator log)
2. EME — moon-ephemeris check, ≥2m band, >1800 km path
3. aurora — Kp≥5 + high-lat path, 50-432 MHz
4. sporadic-E — foEs × 5 ≥ band_mhz, 400-2500 km path
5. meteor_scatter — ±3 days of a shower peak, VHF/UHF
6. rain_scatter — common-volume radar heavy rain, 5-11 GHz ≤800 km
7. tropo_duct — HRRR native_best_duct ≥ band or ducting_detected
8. line_of_sight — ≤50 km path
9. troposcatter — default
Persisted via MechanismClassifyWorker (queue: :mechanism, unique on
contact_id). Submit-time enqueue path includes :mechanism by default;
BackfillEnqueueWorker cron now handles :mechanism alongside existing
types so prod continuously backfills any contact with
propagation_mechanism_status in (:pending, :queued, :failed). Also
added :radar to the cron's type list so common-volume radar backfill
runs automatically rather than only via `mix radar_backfill`.
New modules:
- Microwaveprop.Propagation.MoonEphemeris — Meeus low-precision moon
position, accuracy ±1° — enough for the mutual-visibility EME test
- Microwaveprop.Propagation.MechanismClassifier — plug-in priority
chain over the evidence map
- Microwaveprop.Workers.MechanismClassifyWorker — assembles inputs
from HRRR / native profiles / common-volume radar / solar_indices /
ionosonde + calls the classifier
ADIF importer now reads PROP_MODE into user_declared_prop_mode so
operator-tagged mechanisms (EME/ES/MS/RS/AS/AUR) become ground truth.
