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/PlexBrowse.tsx

@@ -43,6 +43,9 @@ import { useContextMenu } from "./ui/useContextMenu";
 import { PlexInfoView, PlexPersonView, PlexSeasonView, PlexShowView } from "./plexViews";
 import { dispatch, useKeyScope } from "../lib/keymap";
 import NavGrid from "./ui/NavGrid";
+import { Chip } from "./ui/Chip";
+import { IconButton } from "./ui/IconButton";
+import { Pressable } from "./ui/Pressable";
 
 // Lazy: the rich player (pulls in hls.js) loads only when something is first played.
 const PlexPlayer = lazy(() => import("./PlexPlayer"));
@@ -553,10 +556,10 @@ export default function PlexBrowse() {
               className="glass-card flex items-center gap-1 rounded-xl py-1.5 pl-1.5 pr-2.5"
             >
               {/* The photo + name open the actor's filmography page; the ✕ removes the filter. */}
-              <button
+              <Pressable
                 onClick={() => onOpenPerson(p.name)}
                 title={t("plex.info.viewPerson", { name: p.name })}
-                className="group/person flex min-w-0 items-center gap-2.5 rounded-lg text-left"
+                className="group/person flex min-w-0 items-center gap-2.5 rounded-lg"
               >
                 {p.photo ? (
                   <img
@@ -578,15 +581,14 @@ export default function PlexBrowse() {
                     {t("plex.people.count", { count: p.count })}
                   </div>
                 </div>
-              </button>
-              <button
+              </Pressable>
+              <IconButton
                 onClick={() => removeActor(p.name)}
-                title={t("plex.people.remove")}
-                aria-label={t("plex.people.remove")}
-                className="ml-1 p-1 rounded-full text-muted hover:text-fg hover:bg-card transition"
+                label={t("plex.people.remove")}
+                className="ml-1"
               >
-                <X className="w-4 h-4" />
-              </button>
+                <X />
+              </IconButton>
             </div>
           ))}
         </div>
@@ -604,12 +606,9 @@ export default function PlexBrowse() {
           // query — say so and offer a one-click escape, instead of a bare "No matches".
           <div className="flex flex-wrap items-center gap-3 text-sm text-muted">
             <span>{t("plex.noMatchesFiltered", { count: plexFilterCount(filters) })}</span>
-            <button
-              onClick={() => setFilters(EMPTY_PLEX_FILTERS)}
-              className="rounded-full border border-border bg-card px-3 py-1 text-xs font-medium transition hover:border-accent hover:text-accent"
-            >
+            <Chip onClick={() => setFilters(EMPTY_PLEX_FILTERS)} className="font-medium">
               {t("plex.filter.clearAll")}
-            </button>
+            </Chip>
           </div>
         ) : (
           <p className="text-muted text-sm">{dq ? t("plex.noMatches") : t("plex.empty")}</p>