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/ShareDialog.tsx

@@ -3,7 +3,6 @@ import { qk } from "../lib/queryKeys";
 import { useTranslation } from "react-i18next";
 import { useMutation, useQuery, useQueryClient } from "@tanstack/react-query";
 import { Check, Copy, Link2, Lock, Trash2, UserPlus, Eye } from "lucide-react";
-import clsx from "clsx";
 import Modal from "./ui/Modal";
 import { useConfirm } from "./confirmContext";
 import { notify } from "../lib/notifications";
@@ -14,7 +13,7 @@ import { api, type DownloadJob, type ShareLink, type ShareRecipient } from "../l
 import { inputCls } from "./ui/form";
 import { Button } from "./ui/Button";
 import { IconButton } from "./ui/IconButton";
-import { FocusSafeButton } from "./ui/FocusSafeButton";
+import { Pressable } from "./ui/Pressable";
 const EXPIRY_DAYS = [null, 1, 7, 30] as const;
 
 // --- share with a registered user (ACL) -----------------------------------------------------
@@ -72,15 +71,16 @@ function UserShare({ job }: { job: DownloadJob }) {
         {open && filtered.length > 0 && (
           <div className="absolute z-base mt-1 w-full rounded-lg glass-menu overflow-hidden">
             {filtered.map((u) => (
-              <FocusSafeButton
+              <Pressable
                 key={u.id}
+                layer
                 onClick={() => share.mutate(u.email)}
                 disabled={share.isPending}
-                className="w-full text-left px-3 py-2 text-sm hover:bg-surface transition flex flex-col"
+                className="w-full px-3 py-2 text-sm flex flex-col"
               >
                 <span className="truncate">{u.display_name || u.email}</span>
                 {u.display_name && <span className="text-xs text-muted truncate">{u.email}</span>}
-              </FocusSafeButton>
+              </Pressable>
             ))}
           </div>
         )}
@@ -227,15 +227,18 @@ function LinkRow({ link, onChanged }: { link: ShareLink; onChanged: () => void }
             )}
             className="flex-1 min-w-0 bg-surface border border-border rounded-md px-2 py-1 text-xs focus:outline-hidden focus:ring-2 focus:ring-accent/40"
           />
-          <FocusSafeButton
+          <Button
+            size="xs"
             onClick={() => savePass.mutate(newPass.trim())}
-            disabled={savePass.isPending || !newPass.trim()}
-            className="px-2 py-1 rounded-md text-xs font-semibold btn-primary disabled:opacity-40 transition"
+            loading={savePass.isPending}
+            disabled={!newPass.trim()}
           >
             {t("downloads.share.savePassword")}
-          </FocusSafeButton>
+          </Button>
           {link.has_password && (
-            <FocusSafeButton
+            <Button
+              variant="outline-danger"
+              size="xs"
               onClick={async () => {
                 if (
                   await confirm({
@@ -248,10 +251,9 @@ function LinkRow({ link, onChanged }: { link: ShareLink; onChanged: () => void }
                   savePass.mutate("");
               }}
               disabled={savePass.isPending}
-              className="px-2 py-1 rounded-md text-xs text-muted hover:text-danger transition"
             >
               {t("downloads.share.removePassword")}
-            </FocusSafeButton>
+            </Button>
           )}
         </div>
       )}
@@ -336,20 +338,17 @@ function LinkShare({ job }: { job: DownloadJob }) {
           <div className="flex items-center gap-2 text-sm">
             <span className="text-muted">{t("downloads.share.expiry")}:</span>
             {EXPIRY_DAYS.map((d) => (
-              <button
+              <Button
                 key={String(d)}
+                variant="outline"
+                size="xs"
+                pressed={expiryDays === d}
                 onClick={() => setExpiryDays(d)}
-                className={clsx(
-                  "px-2 py-1 rounded-md border text-xs transition",
-                  expiryDays === d
-                    ? "border-accent bg-accent/10 text-accent"
-                    : "border-border text-muted hover:text-fg",
-                )}
               >
                 {d === null
                   ? t("downloads.share.expiryNever")
                   : t("downloads.share.days", { n: d })}
-              </button>
+              </Button>
             ))}
           </div>
           <input