Add migration to widen window_duration_hours precision and update related components for duration handling

apps/edr-freight-api/src/modules/train-scheduling/dto/update-train-scheduling-global-rules.dto.ts

@@ -60,11 +60,13 @@ export class UpdateTrainSchedulingGlobalRulesDto {
   @Max(23)
   windowOpenHour?: number;
 
+  // Stored in hours. The UI enters this in minutes/hours/days and converts to
+  // hours before sending, so the floor is 1 minute (0.0166h) — not 15 min.
   @ApiPropertyOptional({ example: 3 })
   @IsOptional()
   @Type(() => Number)
   @IsNumber()
-  @Min(0.25)
+  @Min(0.0166)
   @Max(12)
   windowDurationHours?: number;