eighth version

internal/repository/mysql/repository.go

@@ -356,7 +356,7 @@ INSERT INTO candles_minute (
   :instrument_uid, :trade_date, :open, :high, :low, :close, :volume_lots, :source, :loaded_at
 ) ON DUPLICATE KEY UPDATE
   open=VALUES(open), high=VALUES(high), low=VALUES(low), close=VALUES(close),
-  volume_lots=VALUES(volume_lots), source=VALUES(source), loaded_at=VALUES(loaded_at)`, candleRowFromDomain(candle))
+  volume_lots=VALUES(volume_lots), source=VALUES(source), loaded_at=VALUES(loaded_at)`, minuteCandleRowFromDomain(candle))
 		if err != nil {
 			return err
 		}

internal/repository/mysql/rows.go

@@ -35,6 +35,20 @@ func candleRowFromDomain(candle domain.Candle) candleRow {
 	}
 }
 
+func minuteCandleRowFromDomain(candle domain.Candle) candleRow {
+	return candleRow{
+		InstrumentUID: candle.InstrumentUID,
+		TradeDate:     candle.TradeDate.UTC(),
+		Open:          candle.Open,
+		High:          candle.High,
+		Low:           candle.Low,
+		Close:         candle.Close,
+		VolumeLots:    candle.VolumeLots,
+		Source:        candle.Source,
+		LoadedAt:      candle.LoadedAt,
+	}
+}
+
 func (r candleRow) domain() domain.Candle {
 	return domain.Candle{
 		InstrumentUID: r.InstrumentUID,

internal/repository/mysql/rows_test.go

@@ -0,0 +1,27 @@
+package mysql
+
+import (
+	"testing"
+	"time"
+
+	"github.com/shopspring/decimal"
+
+	"overnight-trading-bot/internal/domain"
+)
+
+func TestMinuteCandleRowPreservesTimestamp(t *testing.T) {
+	ts := time.Date(2026, 6, 8, 15, 25, 30, 123000000, time.UTC)
+	row := minuteCandleRowFromDomain(domain.Candle{
+		InstrumentUID: "uid",
+		TradeDate:     ts,
+		Open:          decimal.NewFromInt(1),
+	})
+	if !row.TradeDate.Equal(ts) {
+		t.Fatalf("minute timestamp=%s, want %s", row.TradeDate, ts)
+	}
+
+	daily := candleRowFromDomain(domain.Candle{InstrumentUID: "uid", TradeDate: ts})
+	if daily.TradeDate.Equal(ts) || daily.TradeDate.Hour() != 0 || daily.TradeDate.Minute() != 0 {
+		t.Fatalf("daily timestamp was not truncated to date: %s", daily.TradeDate)
+	}
+}