Add Before.Console — console app demonstrating ActiveRecord pattern

Scaffold Before.Console project referencing the Before library.
Implements a straight-line demo that creates clients/orders, saves
them via DbBase.Context (singleton), lists all clients with orders,
and finds a client by name using Client.FindByName().

src/Before.Console/Before.Console.csproj

@@ -0,0 +1,14 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net10.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\Before\Before.csproj" />
+  </ItemGroup>
+
+</Project>

src/Before.Console/Program.cs

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+using Before;
+
+// ---------------------------------------------------------------------------
+// Before.Console — a straight-line demo of the ActiveRecord-style pattern.
+//
+// The console app sets DbBase.Context (the shared singleton) once at startup,
+// then creates client/order entities, saves them through the context, and
+// queries back using the ActiveRecord entry points:
+//   • Client.FindByName(name, context)
+//   • listing via DbBase.Context!.Tracked
+// ---------------------------------------------------------------------------
+
+var ctx = new DbContext();
+DbBase.Context = ctx;
+
+// ----- seed data ----------------------------------------------------------
+var jane = new Client { Name = "Jane Doe" };
+var bob  = new Client { Name = "Bob Smith" };
+
+jane.Orders.Add(new Order { Description = "Design consultation" });
+jane.Orders.Add(new Order { Description = "Website redesign" });
+
+bob.Orders.Add(new Order { Description = "Monthly retainer" });
+
+// Orders need to be attached too so they get IDs:
+ctx.Attach(jane.Orders[0]);
+ctx.Attach(jane.Orders[1]);
+ctx.Attach(bob.Orders[0]);
+
+ctx.Attach(jane);
+ctx.Attach(bob);
+ctx.Save();
+
+// ----- list all clients ---------------------------------------------------
+Console.WriteLine("=== All Clients ===");
+foreach (var client in DbBase.Context!.Tracked.OfType<Client>())
+{
+    Console.WriteLine($"{client.Name} [{client.Id}]");
+    foreach (var order in client.Orders)
+        Console.WriteLine($"  - order [{order.Id}]: {order.Description}");
+}
+
+// ----- find by name -------------------------------------------------------
+Console.WriteLine("\n=== Find by Name ===");
+var found = Client.FindByName("Jane Doe", DbBase.Context);
+if (found is not null)
+{
+    Console.WriteLine($"Found: {found.Name} [{found.Id}]");
+    Console.WriteLine($"  Orders: {found.Orders.Count}");
+}
+else
+{
+    Console.WriteLine("Not found.");
+}