Port of Microwaveprop.Commercial.build_link_lookup/2 +
link_degradation_from_lookup/3. The Elixir context stays intact
(LiveView sensor + SNMP poller); this Rust side is the read-only
consumer used by the f00 chain step (Phase 3 Stream A).
Three pure-math unit tests cover: haversine distance (DFW→Austin and
same-point zero), degradation_at aggregation behaviour, and
two-decimal rounding convention that Elixir's Float.round(_, 2)
imposes. SQL queries mirror the Elixir Ecto queries one-for-one —
baseline window, current point-in-time read, and MIN_BASELINE_SAMPLES
quality gate.
Graham McIntire
9f36e78397