fix(python): python binding of Compaction.commit

[gstamatakis95]

Closes #7209

• python/src/dataset/optimize.rs: Compaction.commit gains an optional options dict
  parameter (#[pyo3(signature = (dataset, rewrites, options = None))]), parsed through the same
  parse_compaction_options helper that plan and execute already use, seeded from the
  dataset's manifest.config exactly like execute. Absent or None preserves the old behavior.
  The TODO comment is removed.
• python/python/lance/lance/optimize.pyi: stub updated to
  commit(dataset, rewrites, options: Optional[CompactionOptions] = None).
• python/python/tests/test_optimize.py: new parametrized test
  test_defer_index_remap_via_commit_options. With
  Compaction.commit(dataset, rewrites, options={"defer_index_remap": True}) a
  __lance_frag_reuse system index appears in describe_indices(). Without options it does not
  (inline remap occurs). Mirrors the adjacent test_defer_index_remap setup.