Refactor and enhance tests for call graph extractors and connection management

- Updated JavaScriptCallGraphExtractorTests to improve naming conventions and test cases for Azure Functions, CLI commands, and socket handling.
- Modified NodeCallGraphExtractorTests to correctly assert exceptions for null inputs.
- Enhanced WitnessModalComponent tests in Angular to use Jasmine spies and improved assertions for path visualization and signature verification.
- Added ConnectionState property for tracking connection establishment time in Router.Common.
- Implemented validation for HelloPayload in ConnectionManager to ensure required fields are present.
- Introduced RabbitMqContainerFixture method for restarting RabbitMQ container during tests.
- Added integration tests for RabbitMq to verify connection recovery after broker restarts.
- Created new BinaryCallGraphExtractorTests, GoCallGraphExtractorTests, and PythonCallGraphExtractorTests for comprehensive coverage of binary, Go, and Python call graph extraction functionalities.
- Developed ConnectionManagerTests to validate connection handling, including rejection of invalid hello messages and proper cleanup on client disconnects.

src/__Libraries/StellaOps.Router.Common/Models/ConnectionState.cs

@@ -22,6 +22,11 @@ public sealed class ConnectionState
     /// </summary>
     public InstanceHealthStatus Status { get; set; } = InstanceHealthStatus.Unknown;
 
+    /// <summary>
+    /// Gets the UTC timestamp when this connection was established.
+    /// </summary>
+    public DateTime ConnectedAtUtc { get; init; } = DateTime.UtcNow;
+
     /// <summary>
     /// Gets or sets the UTC timestamp of the last heartbeat.
     /// </summary>