The 5 haversine SQL fragments duplicated across StationController and
NationalFuelPredictionService disagreed on float-clamping (LEAST only,
GREATEST/LEAST, vs. CASE WHEN). Centralised in App\Services\HaversineQuery
with the safe GREATEST(-1.0, LEAST(1.0, …)) form everywhere.
withinKm() embeds the radius as a numeric literal (sprintf %F) because
PDO + SQLite binds float parameters as strings by default, which breaks
numeric comparison against the haversine expression — a NULL filter would
silently match all rows. Coordinates remain bound positionally.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>