- add shared Base UI-backed checkbox and slider primitives under the form component layer
- move the singles import checkbox and auto-import confidence slider to the shared controls
- keep the import route tests aligned with the new accessible component roles
- replace index-based singles selection and search state with stable staging file keys\n- keep refreshes from shifting selected rows or open search panels when files are inserted or reordered\n- add a regression test that proves selection stays attached to the intended file across refreshes
- Move import page, tabs, workflow state, and route tests into React-owned route slices
- Preserve shell gating, staging queries, album matching, singles matching, auto-import, and queue behavior
- Add migration plan snapshot so cleanup/refinement can build on a stable baseline