[VECTOR_FLOAT16] Implement feature extension and version negotiation for Vector v2 support

[muskan124947]

Description

For upcoming VECTOR_FLOAT16 support in the Microsoft JDBC Driver for SQL Server, this PR introduces the initial framework for vector type support handling on the client side, enabling controlled negotiation of vector capabilities between client and server.

The changes focus on making vector support explicit, extensible, and future-proof, in preparation for additional vector versions and data types.

Vector Version Negotiation Flow

• The client vector setting is parsed and validated:

off – vector support disabled
v1 – float32 vector support
v2 – float32 and float16 vector support

• If either the client disables vectors or the server does not support vectors, vector support is disabled.
• The client and server determine their maximum supported vector versions.
• When both support vectors, the negotiated version is the minimum of the client and server versions.
• The negotiated version is used for all vector-related operations for the connection.

Impact

• Backward compatibility: Clients using only float32 continue to work without changes.
• Performance: Float16 support reduces memory usage and network payload for supported operations.
• Extensibility: Framework allows easy addition of future vector types and versions.

[codecov]

Codecov Report

❌ Patch coverage is 50.90909% with 27 lines in your changes missing coverage. Please review.
✅ Project coverage is 59.20%. Comparing base (19d385f) to head (f09d152).

Files with missing lines	Patch %	Lines
.../microsoft/sqlserver/jdbc/SQLServerConnection.java	44.82%	12 Missing and 4 partials ⚠️
.../com/microsoft/sqlserver/jdbc/SQLServerDriver.java	57.69%	9 Missing and 2 partials ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##               main    #2868      +/-   ##
============================================
- Coverage     59.23%   59.20%   -0.04%     
- Complexity     4797     4809      +12     
============================================
  Files           151      151              
  Lines         34781    34825      +44     
  Branches       5829     5834       +5     
============================================
+ Hits          20604    20618      +14     
- Misses        11380    11416      +36     
+ Partials       2797     2791       -6     

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[muskan124947]

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[Copilot]

Pull request overview

This PR extends the Microsoft SQL Server JDBC driver’s vector feature support to introduce an explicit vectorTypeSupport version model, including v2 (float32 + float16) and client–server negotiation of supported vector versions.

Changes:

• Introduces a VectorTypeSupport enum and TDS constants for vector feature extension, wiring them into connection properties and feature negotiation during login.
• Adds client–server vector version negotiation in SQLServerConnection, with a tracked negotiatedVectorVersion and a getter, and updates resource strings and public APIs (ISQLServerConnection, ISQLServerDataSource, pool proxy) to document v2 support.
• Updates tests and helpers (e.g., VectorTest and property metadata) to recognize "v2" as a valid vectorTypeSupport value and to support float16-specific behavior.

Reviewed changes

Copilot reviewed 8 out of 8 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
src/main/java/com/microsoft/sqlserver/jdbc/SQLServerDriver.java	Adds VectorTypeSupport enum mapping logical values to TDS versions, updates the vectorTypeSupport driver property default, and exposes the allowed values via SQLServerDriverPropertyInfo for configuration tooling.
src/main/java/com/microsoft/sqlserver/jdbc/SQLServerConnection.java	Reworks vector-type configuration to use VectorTypeSupport, adds negotiatedVectorVersion state, integrates vector version negotiation into feature extension ACK handling, and exposes getNegotiatedVectorVersion().
src/main/java/com/microsoft/sqlserver/jdbc/IOBuffer.java	Extends TDS constants for vector support to define explicit v1 and v2 values and updates the maximum supported version to 2.
src/main/java/com/microsoft/sqlserver/jdbc/SQLServerResource.java	Updates resource strings for vectorTypeSupport to document the new valid value "v2" and keep error messages aligned with the property’s semantics.
src/main/java/com/microsoft/sqlserver/jdbc/ISQLServerConnection.java	Updates the setVectorTypeSupport / getVectorTypeSupport Javadoc to describe v2, aligning the public connection interface with the extended vector support options.
src/main/java/com/microsoft/sqlserver/jdbc/ISQLServerDataSource.java	Mirrors the vectorTypeSupport documentation updates on the DataSource API to include v2 and clarify behavior.
src/main/java/com/microsoft/sqlserver/jdbc/SQLServerConnectionPoolProxy.java	Propagates and documents the extended vectorTypeSupport property through the pooled connection proxy.
src/test/java/com/microsoft/sqlserver/jdbc/datatypes/VectorTest.java	Extends the test helper connection factory to accept "v2" as a valid vectorTypeSupport value while otherwise preserving existing vector behavior tests.

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[Copilot]

Pull request overview

Copilot reviewed 8 out of 8 changed files in this pull request and generated 2 comments.

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[Copilot]

The new negotiateVectorVersion logic introduces non-trivial behavior (e.g., handling client OFF vs. server NOT_SUPPORTED, client V2 vs. server V1, etc.), but there do not appear to be tests that directly validate these negotiation outcomes or the negotiatedVectorVersion field. Given that other SQLServerConnection behaviors are covered by tests (for example, see RequestBoundaryMethodsTest.setConnectionFields / compareValuesAgainstConnection), consider adding targeted tests that exercise this negotiation for the key combinations of client and server versions to guard against regressions.