fix(schema): one device per fill in v_fuel_fills (LATERAL + LIMIT 1)

A plate can map to multiple tracksolid.devices rows (vehicle re-fitted with a
new tracker), so the plain LEFT JOIN fanned out and double-counted litres/spend
(3345 view rows for 1888 live records). LATERAL ... ORDER BY enabled_flag,
updated_at LIMIT 1 picks one device per fill. Applied to prod as migration 02;
01 updated so fresh installs are correct. Verified: 1888 rows, 1775 matched.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

migrations/01_fuel_schema.sql

@@ -157,7 +157,7 @@ CREATE OR REPLACE VIEW reporting.v_fuel_fills AS
         d.vehicle_number,
         d.cost_centre,
         d.assigned_city,
-        d.driver_name           AS assigned_driver,
+        d.assigned_driver,
         d.imei,
         r.department,
         r.driver,
@@ -166,7 +166,19 @@ CREATE OR REPLACE VIEW reporting.v_fuel_fills AS
         r.fuel_type,
         r.odometer
    FROM fuel.records r
-   LEFT JOIN tracksolid.devices d ON fuel.norm_plate(d.vehicle_number) = r.plate
+   -- LATERAL + LIMIT 1: a plate can map to more than one devices row (vehicle
+   -- re-fitted with a new tracker over time). Pick exactly ONE — prefer an
+   -- enabled, most-recently-updated device — so each fill yields a single row
+   -- (a plain LEFT JOIN fans out and double-counts litres/spend).
+   LEFT JOIN LATERAL (
+        SELECT dv.vehicle_number, dv.cost_centre, dv.assigned_city,
+               dv.driver_name AS assigned_driver, dv.imei
+          FROM tracksolid.devices dv
+         WHERE r.plate IS NOT NULL
+           AND fuel.norm_plate(dv.vehicle_number) = r.plate
+         ORDER BY dv.enabled_flag DESC NULLS LAST, dv.updated_at DESC NULLS LAST
+         LIMIT 1
+   ) d ON true
   WHERE r.deleted_at IS NULL;
 
 -- ── per-vehicle fuel efficiency: km/litre from consecutive odometer readings ──

migrations/02_fuel_fills_dedupe_join.sql

@@ -0,0 +1,38 @@
+-- 02_fuel_fills_dedupe_join.sql — fleetfuel · fix v_fuel_fills row fan-out
+-- ─────────────────────────────────────────────────────────────────────────────
+-- A plate can map to more than one tracksolid.devices row (a vehicle re-fitted
+-- with a new tracker keeps the same number plate), so the migration-01 plain
+-- LEFT JOIN produced multiple rows per fill and double-counted litres / spend
+-- (v_fuel_fills had ~3345 rows for ~1888 live records). Replace the join with a
+-- LATERAL ... LIMIT 1 that picks exactly one device per fill (prefer enabled,
+-- most-recently-updated), so each fill yields a single row. Columns unchanged,
+-- so dependent reporting.v_fuel_efficiency stays valid. Idempotent.
+-- ─────────────────────────────────────────────────────────────────────────────
+
+CREATE OR REPLACE VIEW reporting.v_fuel_fills AS
+ SELECT r.id,
+        r.record_datetime,
+        r.record_datetime::date AS fuel_date,
+        r.plate,
+        d.vehicle_number,
+        d.cost_centre,
+        d.assigned_city,
+        d.assigned_driver,
+        d.imei,
+        r.department,
+        r.driver,
+        r.liters,
+        r.amount,
+        r.fuel_type,
+        r.odometer
+   FROM fuel.records r
+   LEFT JOIN LATERAL (
+        SELECT dv.vehicle_number, dv.cost_centre, dv.assigned_city,
+               dv.driver_name AS assigned_driver, dv.imei
+          FROM tracksolid.devices dv
+         WHERE r.plate IS NOT NULL
+           AND fuel.norm_plate(dv.vehicle_number) = r.plate
+         ORDER BY dv.enabled_flag DESC NULLS LAST, dv.updated_at DESC NULLS LAST
+         LIMIT 1
+   ) d ON true
+  WHERE r.deleted_at IS NULL;