Wire both insert actions to CurrentTrack (InsertMedia base 0). Per selected
track: SetOnlyTrackSelected, reset cursor to snapshot, InsertMedia; then restore
original selection + cursor. No-op when no track selected. Corrected stale
extraflags / new-track / preservePitch comments.
InsertMedia-driven placement reading the bank panel selection, undo-wrapped.
Native length by default; conform-to-tempo is an explicit second action, never
a silent stretch. Pure mode-bit logic (insert_plan) unit-tested.
daniel