support targeting specific date

internal/bsdaily/run.go

@@ -5,16 +5,22 @@ import (
 	"log/slog"
 	"os"
 	"path/filepath"
+	"time"
 )
 
-func Run() error {
+func Run(targetDate *time.Time) error {
 	snapshotDir, snapshotDate, err := FindLatestDailySnapshot()
 	if err != nil {
 		return fmt.Errorf("finding latest snapshot: %w", err)
 	}
 	slog.Info("found latest daily snapshot", "dir", snapshotDir, "snapshot_date", snapshotDate.Format("2006-01-02"))
 
-	targetDay := snapshotDate.AddDate(0, 0, -1)
+	var targetDay time.Time
+	if targetDate != nil {
+		targetDay = *targetDate
+	} else {
+		targetDay = snapshotDate.AddDate(0, 0, -1)
+	}
 	slog.Info("target day for extraction", "date", targetDay.Format("2006-01-02"))
 
 	// Check if output already exists