fix(stats): recover durable daily mileage projections

go/vehicle-gateway/internal/stats/daily_metric.go

@@ -95,6 +95,13 @@ type ProjectionFlushResult struct {
 	Failed    int
 }
 
+type ProjectionReconcileResult struct {
+	Targets   int
+	Attempted int
+	Written   int
+	Failed    int
+}
+
 type CacheStats struct {
 	LastTotalMileageEntries  int
 	LastSourceSeenEntries    int
@@ -553,6 +560,62 @@ func (w *Writer) FlushPendingProjections(ctx context.Context, readyBefore time.T
 	return result, flushErr
 }
 
+// ReconcileDateProjections rebuilds final daily rows whose durable source
+// candidates are newer than the projection (or whose projection is missing).
+// The pending queue is intentionally in-memory for the hot path; this durable
+// sweep closes the crash window between a committed source candidate and its
+// throttled final projection.
+func (w *Writer) ReconcileDateProjections(ctx context.Context, statDate string) (ProjectionReconcileResult, error) {
+	var result ProjectionReconcileResult
+	if w.query == nil {
+		return result, errors.New("daily mileage projection reconciliation requires query support")
+	}
+	statDate = strings.TrimSpace(statDate)
+	if statDate == "" {
+		return result, errors.New("daily mileage projection reconciliation requires stat date")
+	}
+	rows, err := w.query.QueryContext(ctx, staleDailyMileageProjectionTargetsSQL, statDate)
+	if err != nil {
+		return result, err
+	}
+	type target struct {
+		vin      string
+		protocol envelope.Protocol
+	}
+	var targets []target
+	for rows.Next() {
+		var item target
+		if err := rows.Scan(&item.vin, &item.protocol); err != nil {
+			_ = rows.Close()
+			return result, err
+		}
+		if strings.TrimSpace(item.vin) != "" && strings.TrimSpace(string(item.protocol)) != "" {
+			targets = append(targets, item)
+		}
+	}
+	if err := rows.Close(); err != nil {
+		return result, err
+	}
+	if err := rows.Err(); err != nil {
+		return result, err
+	}
+	result.Targets = len(targets)
+	var reconcileErr error
+	for _, item := range targets {
+		if err := ctx.Err(); err != nil {
+			return result, errors.Join(reconcileErr, err)
+		}
+		result.Attempted++
+		if err := ProjectDailyMileage(ctx, w.exec, item.vin, statDate, item.protocol); err != nil {
+			result.Failed++
+			reconcileErr = errors.Join(reconcileErr, fmt.Errorf("reconcile daily mileage %s/%s/%s: %w", item.vin, statDate, item.protocol, err))
+			continue
+		}
+		result.Written++
+	}
+	return result, reconcileErr
+}
+
 func (w *Writer) projectPendingMileage(ctx context.Context, sample MetricSample) error {
 	project := func(exec Execer) error {
 		if strings.Contains(sample.SourceKey, platformSourceKeyPrefix) {
@@ -576,6 +639,24 @@ func (w *Writer) projectPendingMileage(ctx context.Context, sample MetricSample)
 	return project(w.exec)
 }
 
+const staleDailyMileageProjectionTargetsSQL = `
+SELECT s.vin, s.protocol
+FROM vehicle_daily_mileage_source s
+LEFT JOIN vehicle_daily_mileage m
+  ON m.vin = s.vin
+ AND m.stat_date = s.stat_date
+ AND m.protocol = s.protocol
+WHERE s.stat_date = ?
+  AND s.quality_status = '` + QualityOK + `'
+  AND (
+    m.vin IS NULL
+    OR s.updated_at > m.updated_at
+    OR s.latest_event_time > m.updated_at
+  )
+GROUP BY s.vin, s.protocol
+ORDER BY s.protocol ASC, s.vin ASC
+`
+
 func (w *Writer) seenSameMileage(sample MetricSample) bool {
 	key := mileageCacheKey(sample)
 	w.mu.Lock()