Add VECTOR and BSON data types support

[okramarenko]

Note

Medium Risk
Medium risk because it changes low-level protocol metadata parsing, type mapping, and parameter serialization, which can affect result reading/writing across many queries. Also introduces a new session-setting toggle gated by server version that could break connections if misconfigured.

Overview
Adds opt-in support for SingleStore extended data types by introducing EnableExtendedDataTypes (connection string + settings) that enables enable_extended_types_metadata during connection open and after connection reset (requires SingleStore >= 8.5.28).

Extends column definition parsing with SingleStore-specific extended metadata (SingleStoreExtendedTypeCode, VECTOR dimensions/element type) and updates type mapping/metadata so BSON/VECTOR surface as SingleStoreDbType.Bson/SingleStoreDbType.Vector while still transporting as BLOB in the wire protocol.

Implements typed VECTOR value reading (new Vector*ColumnReaders returning ReadOnlyMemory<T> with length/endianness validation), adjusts row byte access rules for VECTOR vs BSON, and adds BSON/VECTOR parameter serialization (binary literal for text mode; length-encoded bytes for binary/prepared mode) for common input types.

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[cursor]

Unused IsBson and IsVector properties are dead code

Low Severity

The newly added IsBson and IsVector properties on ColumnDefinitionPayload are never referenced anywhere in the codebase. A grep confirms the only matches are their definitions. All other code that needs to check the extended type uses ExtendedTypeCode directly (e.g., the switch in ColumnReader.Create). These are dead code on an internal class with no consumers.

 

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[cursor]

Cursor Bugbot has reviewed your changes and found 1 potential issue.

There are 2 total unresolved issues (including 1 from previous review).

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[cursor]

WriteBinaryLiteral duplicates inline binary escaping logic

Medium Severity

The new WriteBinaryLiteral method contains identical binary-literal escaping logic to the inline code in AppendSqlString (the byte[]/float[] branch). This security-sensitive SQL escaping logic now exists in two places, meaning a bug fix in one copy could be missed in the other. The existing inline code could call WriteBinaryLiteral instead.

 

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