Adds the ROUND function which returns a numeric value rounded to the specified length or precision.

Changes

• ExpressionFunctions.cs — eight overloads covering all supported numeric types: int, bigint, smallint, tinyint, decimal, float, real, money
• FunctionMetadata.cs — autocomplete/IntelliSense entry
• ExpressionFunctionTests.cs — unit tests for float, int, and bigint overloads covering positive/negative lengths, truncation mode, and null inputs

Usage

SELECT ROUND(123.9995, 3)    -- 124.000
SELECT ROUND(748.58, -1)     -- 750.00
SELECT ROUND(150.75, 0, 1)   -- 150.00  (truncate)
SELECT ROUND(amount, 2)      -- works on any numeric column