Fix ORDER BY on grouped source columns when SELECT uses aliases

[Copilot]

Grouped queries were not honoring ORDER BY when the sort referenced the original grouped column name but the SELECT list exposed that column under an alias. This caused grouped results to remain in input order instead of being sorted.

• Grouped ORDER BY key resolution

  • Update grouped select compilation to resolve ORDER BY keys from the grouped source column when the output row only contains the aliased projection.
  • Preserve existing behavior for ordering by projected names and other grouped expressions.

• Regression coverage

  • Add an issue-focused test covering GROUP BY with aliased projections and ORDER BY on the original column name.
  • Cover both ascending and descending ordering.

alasql(
  'SELECT num AS position, letter AS note FROM ? GROUP BY num, letter ORDER BY num',
  [[
    {num: 100, letter: 'one'},
    {num: 50, letter: 'two'},
    {num: 10, letter: 'two'}
  ]]
);

// before: [{position:100}, {position:50}, {position:10}]
// after:  [{position:10}, {position:50}, {position:100}]

• Fixes Issue with ORDER BY clause by original column name when GROUP BY used #2515