feat(design): every button on its family, the chip primitive, the lint rule (E28 S3b2)

The second half of the button sweep: the remaining hand-rolled buttons in
feature components, the design lab and the components/ui composites now
stand on Button, IconButton, Pressable, Chip or DragHandle.

- Chip + DismissibleChip (filter / token / tag / suggest / ghost, 24px
  floor, 44 on touch) replace five chip geometries; FilterChipGroup
  renders Chips; overflow lanes measure a mirror painted by chipClass.
- The Plex control row is IconButton's player rung (36, 20px glyph,
  round, overlay; 44 on touch); the YT modal bar is on the sm rung with
  pressed cycle toggles and names that survive a folded label.
- New variants: IconButton ghost-accent, danger-soft; Button warn on a
  new state-warn utility. The .btn-{tone} recipes and btnCls are gone.
- Fixed on the way: membership rows (collection editor, Plex playlist
  add) announce checked/mixed; a one-letter tag chip was 21px wide;
  descriptionLinks moved out of lib/ (it renders components).
- local/button-primitive: a raw <button>/<FocusSafeButton> outside the
  control-primitive files is a lint error (contract-tested, seen red).

frontend/src/components/ViewSwitcher.tsx

@@ -3,6 +3,7 @@ import { Check, ChevronDown, type LucideIcon } from "lucide-react";
 import clsx from "clsx";
 import { PopoverItem, PopoverSurface } from "./ui/AnchoredPopover";
 import { useAnchoredPopover } from "./ui/anchoredPopoverHooks";
+import { Pressable } from "./ui/Pressable";
 
 export interface ViewOption<T extends string> {
   id: T;
@@ -59,7 +60,7 @@ export default function ViewSwitcher<T extends string>({
 
   return (
     <>
-      <button
+      <Pressable
         ref={pop.refs.setReference}
         {...pop.getReferenceProps()}
         // The aria-label carries the mode's name at every size — the visible text below is a
@@ -75,7 +76,7 @@ export default function ViewSwitcher<T extends string>({
         <ChevronDown
           className={`h-3.5 w-3.5 shrink-0 text-muted transition-transform ${open ? "rotate-180" : ""}`}
         />
-      </button>
+      </Pressable>
       <PopoverSurface
         popover={pop}
         ariaLabel={label}