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/Data/DesignTimeDbContextFactory.cs

@@ -0,0 +1,27 @@
+using Microsoft.AspNetCore.DataProtection;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.EntityFrameworkCore.Design;
+using Microsoft.Extensions.DependencyInjection;
+
+namespace OTSSignsOrchestrator.Core.Data;
+
+/// <summary>
+/// Design-time factory for EF Core migrations tooling.
+/// </summary>
+public class DesignTimeDbContextFactory : IDesignTimeDbContextFactory<XiboContext>
+{
+    public XiboContext CreateDbContext(string[] args)
+    {
+        var optionsBuilder = new DbContextOptionsBuilder<XiboContext>();
+        optionsBuilder.UseSqlite("Data Source=design-time.db");
+
+        // Set up a temporary DataProtection provider for design-time use
+        var services = new ServiceCollection();
+        services.AddDataProtection()
+            .SetApplicationName("OTSSignsOrchestrator");
+        var sp = services.BuildServiceProvider();
+        var dpProvider = sp.GetRequiredService<IDataProtectionProvider>();
+
+        return new XiboContext(optionsBuilder.Options, dpProvider);
+    }
+}

OTSSignsOrchestrator.Core/Data/XiboContext.cs

@@ -0,0 +1,95 @@
+using Microsoft.AspNetCore.DataProtection;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.EntityFrameworkCore.Storage.ValueConversion;
+using OTSSignsOrchestrator.Core.Models.Entities;
+
+namespace OTSSignsOrchestrator.Core.Data;
+
+public class XiboContext : DbContext
+{
+    private readonly IDataProtectionProvider? _dataProtection;
+
+    public XiboContext(DbContextOptions<XiboContext> options, IDataProtectionProvider? dataProtection = null)
+        : base(options)
+    {
+        _dataProtection = dataProtection;
+    }
+
+    public DbSet<CmsInstance> CmsInstances => Set<CmsInstance>();
+    public DbSet<SshHost> SshHosts => Set<SshHost>();
+    public DbSet<SecretMetadata> SecretMetadata => Set<SecretMetadata>();
+    public DbSet<OperationLog> OperationLogs => Set<OperationLog>();
+    public DbSet<AppSetting> AppSettings => Set<AppSetting>();
+
+    protected override void OnModelCreating(ModelBuilder modelBuilder)
+    {
+        base.OnModelCreating(modelBuilder);
+
+        // --- CmsInstance ---
+        modelBuilder.Entity<CmsInstance>(entity =>
+        {
+            entity.HasIndex(e => e.StackName).IsUnique();
+            entity.HasIndex(e => e.CustomerName);
+            entity.HasQueryFilter(e => e.DeletedAt == null);
+
+            entity.HasOne(e => e.SshHost)
+                .WithMany(h => h.Instances)
+                .HasForeignKey(e => e.SshHostId)
+                .OnDelete(DeleteBehavior.SetNull);
+
+            if (_dataProtection != null)
+            {
+                var protector = _dataProtection.CreateProtector("OTSSignsOrchestrator.CmsInstance");
+                var pwdConverter = new ValueConverter<string?, string?>(
+                    v => v != null ? protector.Protect(v) : null,
+                    v => v != null ? protector.Unprotect(v) : null);
+
+                entity.Property(e => e.XiboPassword).HasConversion(pwdConverter);
+                entity.Property(e => e.XiboUsername).HasConversion(pwdConverter);
+                entity.Property(e => e.TemplateRepoPat).HasConversion(pwdConverter);
+                entity.Property(e => e.CifsPassword).HasConversion(pwdConverter);
+            }
+        });
+
+        // --- SshHost ---
+        modelBuilder.Entity<SshHost>(entity =>
+        {
+            entity.HasIndex(e => e.Label).IsUnique();
+
+            if (_dataProtection != null)
+            {
+                var protector = _dataProtection.CreateProtector("OTSSignsOrchestrator.SshHost");
+                var passphraseConverter = new ValueConverter<string?, string?>(
+                    v => v != null ? protector.Protect(v) : null,
+                    v => v != null ? protector.Unprotect(v) : null);
+                var passwordConverter = new ValueConverter<string?, string?>(
+                    v => v != null ? protector.Protect(v) : null,
+                    v => v != null ? protector.Unprotect(v) : null);
+
+                entity.Property(e => e.KeyPassphrase).HasConversion(passphraseConverter);
+                entity.Property(e => e.Password).HasConversion(passwordConverter);
+            }
+        });
+
+        // --- SecretMetadata ---
+        modelBuilder.Entity<SecretMetadata>(entity =>
+        {
+            entity.HasIndex(e => e.Name).IsUnique();
+        });
+
+        // --- OperationLog ---
+        modelBuilder.Entity<OperationLog>(entity =>
+        {
+            entity.HasIndex(e => e.Timestamp);
+            entity.HasIndex(e => e.InstanceId);
+            entity.HasIndex(e => e.Operation);
+        });
+
+        // --- AppSetting ---
+        modelBuilder.Entity<AppSetting>(entity =>
+        {
+            entity.HasKey(e => e.Key);
+            entity.HasIndex(e => e.Category);
+        });
+    }
+}