selection-mode-state-holder

A small @Stable holder for multi-select in a Compose list — keyed by stable id rather than list position, with every mutation funnelled through one private method so a hard cap on the selection size cannot be bypassed, plus the toggle/clear/select-all semantics that make the two gestures read differently. Use when building bulk actions over a list, when selections drift onto the wrong rows after a reorder or a page…