- Implement ROUND with optional precision parameter
- Add CEIL function for rounding up to nearest integer
- Add FLOOR function for rounding down to nearest integer
- Add ABS function for absolute values with type preservation
- Support all numeric types (int32, int64, float32, double)
- Comprehensive test suite with 20+ test cases covering:
- Positive/negative numbers
- Integer/float type preservation
- Precision handling for ROUND
- Null value error handling
- Edge cases (zero, large numbers)
All tests passing ✅