Implement checkpoint modes with docs/tests and reorganize project file layout

tests/CBDD.Tests/Context/TestExtendedDbContext.cs

@@ -0,0 +1,35 @@
+using ZB.MOM.WW.CBDD.Core.Collections;
+using ZB.MOM.WW.CBDD.Core.Metadata;
+
+namespace ZB.MOM.WW.CBDD.Shared;
+
+/// <summary>
+/// Extended test context that inherits from TestDbContext.
+/// Used to verify that collection initialization works correctly with inheritance.
+/// </summary>
+public partial class TestExtendedDbContext : TestDbContext
+{
+    /// <summary>
+    /// Gets or sets the extended entities.
+    /// </summary>
+    public DocumentCollection<int, ExtendedEntity> ExtendedEntities { get; set; } = null!;
+
+    /// <summary>
+    /// Initializes a new instance of the <see cref="TestExtendedDbContext"/> class.
+    /// </summary>
+    /// <param name="databasePath">Database file path.</param>
+    public TestExtendedDbContext(string databasePath) : base(databasePath)
+    {
+        InitializeCollections();
+    }
+
+    /// <inheritdoc />
+    protected override void OnModelCreating(ModelBuilder modelBuilder)
+    {
+        base.OnModelCreating(modelBuilder);
+
+        modelBuilder.Entity<ExtendedEntity>()
+            .ToCollection("extended_entities")
+            .HasKey(e => e.Id);
+    }
+}