feat(tables): a glyph pager with first/last, and tablet-width columns step aside

The pager is four named arrows round the page box (first, previous,
next, last). A table hides a tabletHidden column below 64rem of its own
width, as narrowHidden does below 42rem, through one shared helper that
also hides the column's <col>. The Channels table drops Prio, About and
Length there: at 1024 the channel name had 60 px.

frontend/src/lib/tableColumns.ts

@@ -42,6 +42,28 @@ export interface Column<T> {
   // no width. The table's own width, not the viewport's (an `@container` round it): beside the
   // playlist rail a desktop window gave the table 432 px, and the title column was 0 px wide.
   narrowHidden?: boolean;
+  // …and one a table leaves out while it is narrower than 64rem — a 1024 tablet window, or a desktop
+  // one beside a panel: a secondary column that gives its room back to the name (the owner,
+  // 2026-09-27: at 1024 the channel name had 60 px while About took as much). Same `@container` rule.
+  tabletHidden?: boolean;
+}
+
+// The classes that hide a column below its width (`narrowHidden` / `tabletHidden`), for its cells and,
+// in a fixed layout, for its <col> too: a hidden cell under a <col> that keeps its width would leave an
+// empty stripe. The table's OWN width decides, so the caller wraps the table in an `@container`.
+// Whole literals, because Tailwind only generates a class it can read in one piece.
+const HIDE_BELOW = {
+  narrow: { cell: " hidden @2xl:table-cell", col: " hidden @2xl:table-column" },
+  tablet: { cell: " hidden @5xl:table-cell", col: " hidden @5xl:table-column" },
+} as const;
+
+export function columnHideClass(
+  col: { narrowHidden?: boolean; tabletHidden?: boolean },
+  part: "cell" | "col" = "cell",
+): string {
+  if (col.narrowHidden) return HIDE_BELOW.narrow[part];
+  if (col.tabletHidden) return HIDE_BELOW.tablet[part];
+  return "";
 }
 
 export type FilterMap = Record<string, string | string[]>;