The commercial schema uses uuid primary keys everywhere in this project
(all schemas: `@primary_key {:id, :binary_id, autogenerate: true}`), but
the Rust port bound SELECTs against commercial_links.id and
commercial_samples.link_id as i64. The f00 analysis step failed on first
contact with:
error occurred while decoding column 0: mismatched types; Rust type
`i64` (as SQL type `INT8`) is not compatible with SQL type `UUID`
Switched LinkLookupEntry.link_id and fetch_per_link_degradation's
parameter to uuid::Uuid, updated the sqlx::query_as tuple type, and
patched the test helper to build distinct UUIDs from a byte tag so the
no-range / aggregation / rounding tests still exercise the same
identity semantics without needing a real DB column.
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.
