Add calculated measures support for expressions with aggregates

This commit adds functionality for handling:
- Calculated measures with a simple predefined measure + operator + constant
  (e.g., count(*) * 2)
- Calculated measures with two simple predefined measures + operator
  (e.g., count(*) + sum(col))

Key changes:
- Add _ParseState class for tracking quote/bracket/paren state
- Add _find_top_level_operator to find operators at depth 0
- Add _find_matching_paren, _is_inside_quotes_or_brackets helpers
- Add _count_outer_parens helper for parenthesis handling
- Add _has_operators_outside_quotes helper
- Add _extract_aggregates_from_expression to extract aggregates from
  calculated measures and replace with references
- Add _contains_aggregate_function for optimized aggregate detection
- Add pre-compiled KQL_AGG_PATTERN for performance
- Update _convert_quoted_columns to also convert standalone "col" -> ["col"]
- Update _escape_and_quote_columns to check operators BEFORE stripping quotes
- Update _get_projection_or_summarize to handle calculated measure cases
- Update _extract_maybe_agg_column_parts for multi-arg KQL aggregates

Test updates:
- Update test_group_by_text for new extend column ordering
- Update test_function_text for new extend column ordering
- Update test_group_by_text_vaccine_dataset to not expect redundant extend

Deleted original.py reference file to fix lint errors.

Author: Alison Gim