feat(AliasDataFrame): Add profiling interface for performance debugging

- Add _run_with_profiling() helper method
- Add profile and profile_output parameters to materialize_alias() and materialize_aliases()
- Zero overhead when profile=False (just one if check)
- Output shows both cumulative and total time sorted results
- Optional file output via profile_output parameter

Usage:
  adf.materialize_aliases(names=['x'], profile=True)
  adf.materialize_alias('y', profile=True, profile_output='profile.txt')

Also adds:
- test_profiling.py: Tests for profiling interface
- benchmark_join_caching.py: Baseline benchmark for Phase 2 join caching

Tests: 566 passed, 2 xpassed

Author: miranov25