feat: add date range filter to marketing list API

Added start_date, end_date, and filter_by query parameters to the
GET /api/marketing/ endpoint. Users can now filter marketing records
by a date range using either so_date (Sales Order date, default) or
created_at as the target column.

Changes:
- validation: added StartDate, EndDate (YYYY-MM-DD format), and
  FilterBy (oneof: so_date, created_at) to DeliveryOrderQuery struct
- controller: parse the three new query params in GetAll handler
- service: apply >=start / <end+1day date range filter in the query
  modifier using the existing utils.ParseDateRangeForQuery helper

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

internal/modules/marketing/services/deliveryorder.service.go

@@ -321,6 +321,21 @@ func (s deliveryOrdersService) GetAll(c *fiber.Ctx, params *validation.DeliveryO
 			return db.Where("id = ?", params.MarketingId)
 		}
 
+		dateStart, dateEnd, dateErr := utils.ParseDateRangeForQuery(params.StartDate, params.EndDate)
+		if dateErr != nil {
+			return db.Where("1 = 0")
+		}
+		dateCol := "marketings.so_date"
+		if strings.TrimSpace(params.FilterBy) == "created_at" {
+			dateCol = "marketings.created_at"
+		}
+		if dateStart != nil {
+			db = db.Where(dateCol+" >= ?", *dateStart)
+		}
+		if dateEnd != nil {
+			db = db.Where(dateCol+" < ?", *dateEnd)
+		}
+
 		orderDir := "DESC"
 		if params.SortOrder != "" {
 			orderDir = strings.ToUpper(params.SortOrder)