fix: only use astformat.String for window functions with OVER clause

The previous change broke json_extract and other multi-argument functions
because astformat.String doesn't apply the same recursive processing to
arguments that the manual construction does.

Now only use astformat.String when expr.Over != nil (actual window
functions), keeping the original fmt.Sprintf behavior for regular
functions to maintain proper argument decoration.

Author: claude

internal/stackql/parserutil/parser_util.go

@@ -676,8 +676,14 @@ func inferColNameFromExpr(
 					exprsDecorated = append(exprsDecorated, rv.DecoratedColumn)
 				}
 			}
-			// Use astformat.String to include OVER clause for window functions
-			decoratedColumn := astformat.String(expr, formatter)
+			// Use astformat.String for window functions to include OVER clause,
+			// otherwise use the manually constructed decorated column for proper arg handling
+			var decoratedColumn string
+			if expr.Over != nil {
+				decoratedColumn = astformat.String(expr, formatter)
+			} else {
+				decoratedColumn = fmt.Sprintf("%s(%s)", funcNameLowered, strings.Join(exprsDecorated, ", "))
+			}
 			if retVal.Name != constants.SQLFuncJSONExtractPostgres {
 				retVal.DecoratedColumn = getDecoratedColRendition(decoratedColumn, alias)
 			}