[VECTOR_FLOAT16] Implement serialization and deserialization logic

[muskan124947]

Description

For upcoming VECTOR_FLOAT16 support in the Microsoft JDBC Driver for SQL Server, this change introduces complete serialization and deserialization logic for half-precision floating-point values used inside vector columns.

The driver performs IEEE-754–compliant bidirectional conversion between standard Java Float[] (FLOAT32, 4 bytes) and the compact FLOAT16 (2 bytes) wire format. Applications continue interacting with Float[], while the driver transparently handles precision conversion depending on the negotiated vector type.

Data Flow

Direction	Client Representation	Wire Representation	Conversion Performed
Write (Client → Server)	Float[] (4 bytes each)	FLOAT16 (2 bytes each)	32-bit → 16-bit
Read (Server → Client)	FLOAT16 (2 bytes each)	Float[] (4 bytes each)	16-bit → 32-bit

Conversions Added

• floatToFloat16() : Converts a 32-bit float into its IEEE-754 half-precision (16-bit) representation, applying correct rounding, overflow handling, and encoding of NaN/Infinity.
• float16ToFloat() : Converts a 16-bit half-precision value back into a 32-bit float, preserving sign, exponent, and all special values.
• serializeFloat16Array() : Converts a Float[] into a compact byte array by encoding each element as float16, including support for null markers and special floating-point values.
• deserializeFloat16Array() : Converts a float16 byte array back into a Float[], restoring each element to its 32-bit float form with correct decoding of NaN, Infinity, and nulls.

Motivation

This enhancement enables efficient storage and transmission of VECTOR_FLOAT16 data between Java applications and SQL Server, providing a foundation for vector search, embeddings, and machine-learning workflows that benefit from reduced memory footprint.

[codecov]

Codecov Report

❌ Patch coverage is 81.81818% with 12 lines in your changes missing coverage. Please review.
✅ Project coverage is 56.44%. Comparing base (caef383) to head (93fc891).
⚠️ Report is 4 commits behind head on main.

Files with missing lines	Patch %	Lines
...java/com/microsoft/sqlserver/jdbc/VectorUtils.java	81.81%	8 Missing and 4 partials ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##               main    #2853      +/-   ##
============================================
+ Coverage     56.36%   56.44%   +0.08%     
- Complexity     4523     4559      +36     
============================================
  Files           151      151              
  Lines         34442    34511      +69     
  Branches       5738     5758      +20     
============================================
+ Hits          19412    19480      +68     
- Misses        12408    12413       +5     
+ Partials       2622     2618       -4     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.