feat: Add main application views and structure

- Implemented CreateInstanceView for creating new instances.
- Added HostsView for managing SSH hosts with CRUD operations.
- Created InstancesView for displaying and managing instances.
- Developed LogsView for viewing operation logs.
- Introduced SecretsView for managing secrets associated with hosts.
- Established SettingsView for configuring application settings.
- Created MainWindow as the main application window with navigation.
- Added app manifest and configuration files for logging and settings.

OTSSignsOrchestrator.Core/Models/Entities/OperationLog.cs

@@ -0,0 +1,48 @@
+using System.ComponentModel.DataAnnotations;
+using System.ComponentModel.DataAnnotations.Schema;
+
+namespace OTSSignsOrchestrator.Core.Models.Entities;
+
+public enum OperationType
+{
+    Create,
+    Update,
+    Delete,
+    TestXibo,
+    TestIdP,
+    DeploymentStatus,
+    Other
+}
+
+public enum OperationStatus
+{
+    Pending,
+    Success,
+    Failure
+}
+
+public class OperationLog
+{
+    [Key]
+    public Guid Id { get; set; } = Guid.NewGuid();
+
+    public OperationType Operation { get; set; }
+
+    public Guid? InstanceId { get; set; }
+
+    [ForeignKey(nameof(InstanceId))]
+    public CmsInstance? Instance { get; set; }
+
+    [MaxLength(200)]
+    public string? UserId { get; set; }
+
+    public OperationStatus Status { get; set; } = OperationStatus.Pending;
+
+    /// <summary>Human-readable message. NEVER includes secret values.</summary>
+    [MaxLength(2000)]
+    public string? Message { get; set; }
+
+    public long? DurationMs { get; set; }
+
+    public DateTime Timestamp { get; set; } = DateTime.UtcNow;
+}