Implement InMemory Transport Layer for StellaOps Router

- Added InMemoryTransportOptions class for configuration settings including timeouts and latency.
- Developed InMemoryTransportServer class to handle connections, frame processing, and event management.
- Created ServiceCollectionExtensions for easy registration of InMemory transport services.
- Established project structure and dependencies for InMemory transport library.
- Implemented comprehensive unit tests for endpoint discovery, connection management, request/response flow, and streaming capabilities.
- Ensured proper handling of cancellation, heartbeat, and hello frames within the transport layer.

tests/StellaOps.Microservice.Tests/StellaMicroserviceOptionsTests.cs

@@ -1,5 +1,5 @@
 using StellaOps.Microservice;
-using StellaOps.Router.Common;
+using StellaOps.Router.Common.Enums;
 using Xunit;
 
 namespace StellaOps.Microservice.Tests;
@@ -40,4 +40,98 @@ public class StellaMicroserviceOptionsTests
         Assert.Equal(5000, config.Port);
         Assert.Equal(TransportType.Tcp, config.TransportType);
     }
+
+    [Fact]
+    public void Validate_ThrowsIfServiceNameEmpty()
+    {
+        // Arrange
+        var options = new StellaMicroserviceOptions
+        {
+            ServiceName = "",
+            Version = "1.0.0",
+            Region = "eu1"
+        };
+
+        // Act & Assert
+        Assert.Throws<InvalidOperationException>(() => options.Validate());
+    }
+
+    [Fact]
+    public void Validate_ThrowsIfVersionInvalid()
+    {
+        // Arrange
+        var options = new StellaMicroserviceOptions
+        {
+            ServiceName = "test",
+            Version = "not-semver",
+            Region = "eu1"
+        };
+
+        // Act & Assert
+        var ex = Assert.Throws<InvalidOperationException>(() => options.Validate());
+        Assert.Contains("not valid semver", ex.Message);
+    }
+
+    [Fact]
+    public void Validate_ThrowsIfNoRouters()
+    {
+        // Arrange
+        var options = new StellaMicroserviceOptions
+        {
+            ServiceName = "test",
+            Version = "1.0.0",
+            Region = "eu1"
+        };
+
+        // Act & Assert
+        var ex = Assert.Throws<InvalidOperationException>(() => options.Validate());
+        Assert.Contains("router endpoint is required", ex.Message);
+    }
+
+    [Fact]
+    public void Validate_AcceptsValidSemver()
+    {
+        // Arrange
+        var options = new StellaMicroserviceOptions
+        {
+            ServiceName = "test",
+            Version = "1.0.0",
+            Region = "eu1",
+            Routers = [new RouterEndpointConfig { Host = "localhost", Port = 5000 }]
+        };
+
+        // Act & Assert - no exception
+        options.Validate();
+    }
+
+    [Fact]
+    public void Validate_AcceptsSemverWithPrerelease()
+    {
+        // Arrange
+        var options = new StellaMicroserviceOptions
+        {
+            ServiceName = "test",
+            Version = "2.1.0-beta.1",
+            Region = "eu1",
+            Routers = [new RouterEndpointConfig { Host = "localhost", Port = 5000 }]
+        };
+
+        // Act & Assert - no exception
+        options.Validate();
+    }
+
+    [Fact]
+    public void DefaultHeartbeatInterval_Is10Seconds()
+    {
+        // Arrange & Act
+        var options = new StellaMicroserviceOptions
+        {
+            ServiceName = "test",
+            Version = "1.0.0",
+            Region = "eu1"
+        };
+
+        // Assert
+        Assert.Equal(TimeSpan.FromSeconds(10), options.HeartbeatInterval);
+    }
 }