Cards have no column headers to sort by, so lift the sort out of DataTable into
one shared state that BOTH views drive and reflect. New lib/columnSort.ts holds
the comparator + click-cycle (one source of truth); DataTable gains an optional
controlled sort (sort + onSortChange) and falls back to its internal persistKey
sort when they're omitted, so every other table is untouched. The subscribed
sort lives in ChannelsProvider, discovery keeps its own (its columns differ);
a new ColumnSortControl dropdown (options derived from the columns' sortable
metadata, feed-style + asc/desc toggle) drives it in cards mode. Per-account,
persisted, per-tab.
peter
9c4dd0163a