refactor(core): reorganize DTOs into Models and ViewModels folders

Move DTOs from ApiContracts to appropriate locations:
- SignalR DTOs → ViewModels (renamed Dto→ViewModel suffix)
- Pipeline DTOs → Models/Pipelines
- UserInfoDto → Models/Auth
- DataUpdateDto → Models/Infrastructure

NEW/src/JdeScoping.Core/Models/Pipelines/PipelineStatusDto.cs

@@ -0,0 +1,17 @@
+namespace JdeScoping.Core.Models.Pipelines;
+
+using JdeScoping.Core.Models.Enums;
+
+/// <summary>
+/// Pipeline schedule status for each update type.
+/// </summary>
+public record PipelineStatusResponse(List<PipelineScheduleStatusDto> Statuses);
+
+public record PipelineScheduleStatusDto(
+    UpdateTypes ScheduleType,
+    DateTime? LastRun,
+    bool LastRunWasSuccessful,
+    DateTime? LastSuccessfulRun,
+    DateTime? NextRequiredRun,
+    bool IsOverdue,
+    int IntervalMinutes);