Feature | Add support for enhanced routing feature extension.

[mdaigle]

Ports #3643 to main

[Copilot]

Pull request overview

This pull request adds support for the Enhanced Routing feature extension to the TDS protocol implementation. Enhanced Routing is a TDS 8.0 feature that allows SQL Server to negotiate advanced routing capabilities during connection establishment. The implementation follows the established pattern for feature extensions in Microsoft.Data.SqlClient.

Changes:

• Adds TDS protocol support for Enhanced Routing feature extension (ID 0x0F) with request/acknowledgment handling
• Implements test infrastructure to validate client-server feature negotiation with three scenarios (enabled, disabled, not acknowledged)
• Refactors TDS.Servers.csproj to remove explicit file enumeration, allowing SDK-style implicit compilation

Reviewed changes

Copilot reviewed 10 out of 10 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
src/Microsoft.Data.SqlClient/src/Microsoft/Data/SqlClient/TdsEnums.cs	Adds constant FEATUREEXT_ENHANCEDROUTINGSUPPORT (0x0F) and flag EnhancedRoutingSupport to FeatureExtension enum
src/Microsoft.Data.SqlClient/src/Microsoft/Data/SqlClient/TdsParser.cs	Implements WriteEnhancedRoutingSupportFeatureRequest to send feature request with no payload, adds call in ApplyFeatureExData
src/Microsoft.Data.SqlClient/src/Microsoft/Data/SqlClient/Connection/SqlConnectionInternal.cs	Adds IsEnhancedRoutingSupportEnabled flag, implements acknowledgment handler in OnFeatureExtAck, adds feature to login request
src/Microsoft.Data.SqlClient/tests/tools/TDS/TDS/TDSFeatureID.cs	Adds EnhancedRoutingSupport (0x0F) to test TDS feature ID enum
src/Microsoft.Data.SqlClient/tests/tools/TDS/TDS.Servers/FeatureExtensionEnablementTriState.cs	New enum for test server tri-state feature control (Disabled, Enabled, DoNotAcknowledge)
src/Microsoft.Data.SqlClient/tests/tools/TDS/TDS.EndPoint/ITDSServerSession.cs	Adds IsEnhancedRoutingSupportEnabled property to server session interface
src/Microsoft.Data.SqlClient/tests/tools/TDS/TDS.Servers/GenericTdsServerSession.cs	Implements IsEnhancedRoutingSupportEnabled property for test server sessions
src/Microsoft.Data.SqlClient/tests/tools/TDS/TDS.Servers/GenericTdsServer.cs	Adds EnableEnhancedRouting property, implements feature request handling in OnLogin7Request, adds CheckEnhancedRoutingSupport method for acknowledgment generation
src/Microsoft.Data.SqlClient/tests/UnitTests/SimulatedServerTests/FeatureExtensionNegotiationTests.cs	New test file with three test scenarios for enhanced routing negotiation (enabled, disabled, not acknowledged)
src/Microsoft.Data.SqlClient/tests/tools/TDS/TDS.Servers/TDS.Servers.csproj	Removes EnableDefaultCompileItems and explicit <Compile> elements to use SDK-style implicit file inclusion