Fix CSA index-aligned state drift

[isty2e]

Summary

CSA keeps several projections aligned to the bank entry order: cluster labels, seed-selection state, stage masks, and refresh masks. Some bank mutations updated those projections under different index assumptions.

This PR fixes two cases:

• Near cluster replacement now assigns the admitted candidate to the nearest entry's cluster, even when the removed entry comes from a different cluster.
• Energy-cut removal now remaps selection state and progression masks after first applying update invalidation in the pre-removal index space.

The shared CSA index-remap helper keeps the removal shift rule in one place instead of duplicating it across selection and progression state objects.

Fixes #33

Validation

• uv run --python 3.11 --extra test pytest tests -q
• uv run --python 3.11 --extra test ruff check pyproject.toml src tests
• uv run --python 3.11 --extra test basedpyright src tests
• git diff --check