D1: F6 — exclude_step_types on make_summary

[jepegit]

Epic D — F6 feature menu · Expose exclude_step_types on make_summary. Gap analysis F5/F6; core#54.

The engine already supports it (summarizers.py, threaded through make_core_summary); cellpy just needs to surface it. Restores the selector-exclusion capability users lost in core#45.

Acceptance

• make_summary(..., exclude_step_types=...) kwarg wired to the core summarizer.
• Documented + tested on a golden cell.

Additive. Part of #696.

[jepegit]

Already satisfied — closing.

exclude_step_types is already surfaced on make_summary and wired end to end (it landed with the CV-partition / #509 work, ahead of this Epic D ticket):

• Explicit, documented kwarg on CellpyCell.make_summary(..., exclude_step_types=...) (cellreader.py:3674, docstring at :3694 referencing v2: slim CellpyCell, public API cleanup, exclude_step_types (V2-09/10/12) #509/core#54).
• Threaded through to the core summarizer: cellreader.py:3762 → _make_summary (:3929) → native_core.py:197/219 → make_core_summary.
• Tested on a golden cell: tests/test_cell_readers.py::test_make_summary_exclude_step_types (subtracts per-cycle excluded-step capacity deltas), plus tests/test_cv_partition.py. Both green.

Acceptance criteria (kwarg wired ✓, documented ✓, tested ✓) are met, so no further work is needed.