- DataTable: keep `pagerNode` NULLABLE. Extracting Pager made it an always-truthy
element, so the `controls` / `bottomControls` guards always fired and a table with
nothing to page rendered empty `my-3` bands (plus an empty in-band PageToolbar).
- ChannelsProvider: `setView` bails when the tab is unchanged (re-selecting the
active tab, or goToFullHistory forcing "subscribed", stacked dead Back entries),
and pushes a FRESH state like setPage does instead of spreading `_chan`/`_yt`
markers into the tab entry.
- Lift the layout into its own narrow context (`useChannelLayout`): App read the
whole ChannelsState for the fade, so every keystroke in the manager's search box
re-rendered the app root.
- Reset the card page when the row set or sort changes (both tabs) — the clamp only
hid a stale page, which came back when the filter was cleared.
- Sort + slice the card rows only in cards mode; table mode was copy-sorting ~300
rows per render for a result nothing read.
- Validate persisted `cardSize` / `sort` (`parseCardSize`, `parseSortState`), matching
the clamp-on-read convention the module's other persisted values already follow;
a corrupt size made the page count NaN and emptied the grid.
- Pager: page-size changes scroll to the top too (they re-slice from a new first item).
- ColumnSortControl: a stored sort naming a column this table no longer offers is
treated as no sort, instead of showing a direction arrow for a sort that isn't applied.
- Drop the stale "rows" layout comments (that variant was retired this sprint).
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