perf: pre-allocate slice capacity in evalRetrieve

Pre-allocate the slice capacity in `evalRetrieve` using `make([]result.Value, 0, len(got))` to avoid multiple reallocations as the slice grows. This is a standard optimization in Go when the maximum size of the resulting slice is known beforehand.

Co-authored-by: suyashkumar <6299853+suyashkumar@users.noreply.github.com>

Author: google-labs-jules[bot]

interpreter/expressions.go

@@ -191,7 +191,7 @@ func (i *interpreter) evalRetrieve(expr *model.Retrieve) (result.Value, error) {
 		return result.Value{}, fmt.Errorf("internal error - retrieve result type should be a list of named types, got %v", listResultType)
 	}
 
-	l := []result.Value{}
+	l := make([]result.Value, 0, len(got))
 	for _, c := range got {
 		r, err := unwrapContained(c)
 		if err != nil {