Enhance TypeAwareConversion to handle blob types for consistent SET/ENUM casting

- Extend TypeAwareConversion to handle IsBlobType in addition to IsTextOnly
- Use TypeAwareConversion consistently for both CHAR and BINARY conversions
- Remove direct ConvertToCollatedString call in binary conversion
- Update function documentation to reflect blob type support
- Simplify convertValue logic by using unified conversion approach

This ensures SET/ENUM types are converted properly for all string and binary
target types through a single, consistent code path.

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <[email protected]>

Author: elianddb

sql/expression/convert.go

@@ -293,9 +293,9 @@ func convertValue(ctx *sql.Context, val interface{}, castTo string, originType s
 	}
 	switch strings.ToLower(castTo) {
 	case ConvertToBinary:
-		// For SET/ENUM types, convert to string first since TypeAwareConversion only handles text types
+		// For SET/ENUM types, convert to string first for blob conversions
 		if types.IsSet(originType) || types.IsEnum(originType) {
-			val, _, _ = types.ConvertToCollatedString(ctx, val, originType)
+			val, _ = types.TypeAwareConversion(ctx, val, originType, types.LongText)
 		}
 		b, _, err := types.LongBlob.Convert(ctx, val)
 		if err != nil {
@@ -477,7 +477,6 @@ func createConvertedDecimalType(length, scale int, logErrors bool) sql.DecimalTy
 	return types.InternalDecimalType
 }
 
-
 // convertHexBlobToDecimalForNumericContext converts byte array value to unsigned int value if originType is BLOB type.
 // This function is called when convertTo type is number type only. The hex literal values are parsed into blobs as
 // binary string as default, but for numeric context, the value should be a number.