feature: users with treatment edit permission should now have working hours defined. the appointment grid is now being drawn based on the doctor's working hours.

backend/src/modules/appointments/dto/column-providers-query.dto.ts

@@ -0,0 +1,9 @@
+import { IsOptional, IsString, Matches } from 'class-validator';
+
+export class ColumnProvidersQueryDto {
+  /** Local calendar date (YYYY-MM-DD) used to resolve weekday working hours. */
+  @IsOptional()
+  @IsString()
+  @Matches(/^\d{4}-\d{2}-\d{2}$/)
+  date?: string;
+}