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/Migrations/20260218140239_AddCustomerAbbrev.cs

@@ -0,0 +1,30 @@
+using Microsoft.EntityFrameworkCore.Migrations;
+
+#nullable disable
+
+namespace OTSSignsOrchestrator.Core.Migrations
+{
+    /// <inheritdoc />
+    public partial class AddCustomerAbbrev : Migration
+    {
+        /// <inheritdoc />
+        protected override void Up(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.AddColumn<string>(
+                name: "CustomerAbbrev",
+                table: "CmsInstances",
+                type: "TEXT",
+                maxLength: 3,
+                nullable: false,
+                defaultValue: "");
+        }
+
+        /// <inheritdoc />
+        protected override void Down(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.DropColumn(
+                name: "CustomerAbbrev",
+                table: "CmsInstances");
+        }
+    }
+}