fix: internal server error because of date parsing

internal/common/exportprogress/export.go

@@ -272,6 +272,34 @@ func BuildWorkbook(moduleTitle string, query *Query, rows []Row) ([]byte, error)
 	return buffer.Bytes(), nil
 }
 
+func ParseActivityDate(value string) (time.Time, error) {
+	trimmed := strings.TrimSpace(value)
+	if trimmed == "" {
+		return time.Time{}, fmt.Errorf("empty activity date")
+	}
+
+	layouts := []string{
+		"2006-01-02",
+		time.RFC3339,
+		time.RFC3339Nano,
+		"2006-01-02 15:04:05Z07:00",
+		"2006-01-02 15:04:05.999999999Z07:00",
+	}
+	for _, layout := range layouts {
+		if parsed, err := time.Parse(layout, trimmed); err == nil {
+			return parsed, nil
+		}
+	}
+
+	if len(trimmed) >= len("2006-01-02") {
+		if parsed, err := time.Parse("2006-01-02", trimmed[:10]); err == nil {
+			return parsed, nil
+		}
+	}
+
+	return time.Time{}, fmt.Errorf("unsupported activity date format: %s", value)
+}
+
 func buildStyles(file *excelize.File) (int, int, int, int, int, int, int, int, int, error) {
 	titleStyle, err := file.NewStyle(&excelize.Style{
 		Font:      &excelize.Font{Bold: true, Size: 18, Color: "1F2937"},