Promote the refine-override field accessors to module-level frozenset
constants (``REFINE_PRESET_OVERRIDE_FIELDS``,
``REFINE_STAGE_OVERRIDE_FIELDS``, ``REFINE_FLAT_KEYS``) so callers
reference a single source of truth instead of recomputing on each
call. Drop the redundant ``dict(deepcopy(value))`` double-copy on the
``torch_compile_kwargs`` legacy path, compress the
``_compile_config_to_torch_kwargs`` docstring, and remove a handful of
comments that just restated the code or named a future PR. Narrow the
schema-parity ``walk_packages`` traversal to
``configs/pipelines/*`` and ``basic/<family>/pipeline_configs`` so the
test no longer imports every heavy model module under ``basic/``.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
