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/AccountPanel.tsx

@@ -13,7 +13,7 @@ import { copyText } from "../lib/clipboard";
 import { formatDateTime } from "../lib/format";
 import { invalidateUserAccess } from "../lib/adminUsers";
 import type { AdminUserAccess, AdminUserRow } from "../lib/api/admin";
-import { FocusSafeButton } from "./ui/FocusSafeButton";
+import { Button } from "./ui/Button";
 
 // The admin's answer to "why can this person not get in?", and the place every recovery action for
 // one account lives (E12 · S5, design option C).
@@ -196,24 +196,28 @@ export default function AccountPanel({
           </div>
           <div className="space-y-2">
             {a.can_activate && (
-              <FocusSafeButton
+              <Button
+                variant="glass"
+                fullWidth
+                icon={<Check />}
+                loading={activate.isPending}
                 onClick={() => activate.mutate()}
-                disabled={activate.isPending}
-                className="w-full glass-card glass-hover flex items-center gap-2 px-3 py-2.5 rounded-lg text-xs border border-accent/40 text-accent disabled:opacity-50 transition"
+                className="border border-accent/40 text-accent"
               >
-                <Check className="w-4 h-4 shrink-0" />
                 <span className="flex-1 text-left">{t("users.account.activate")}</span>
-              </FocusSafeButton>
+              </Button>
             )}
 
-            <FocusSafeButton
+            <Button
+              variant="glass"
+              fullWidth
+              icon={<Send />}
+              loading={resend.isPending}
               onClick={() => resend.mutate()}
               // The demo account's address is never confirmed, and the server refuses to mail it — as
               // it refuses it a set-password link below (deep-review E11 round 3).
-              disabled={user.is_demo || !a.email_configured || a.email_verified || resend.isPending}
-              className="w-full glass-card glass-hover flex items-center gap-2 px-3 py-2.5 rounded-lg text-xs disabled:opacity-45 transition"
+              disabled={user.is_demo || !a.email_configured || a.email_verified}
             >
-              <Send className="w-4 h-4 shrink-0" />
               <span className="flex-1 text-left">{t("users.account.resend")}</span>
               {/* Says WHY it is unavailable instead of just greying out — the no-mail case is the
                     whole reason the link below exists, so naming it here is the explanation. */}
@@ -223,18 +227,21 @@ export default function AccountPanel({
               {a.email_configured && a.email_verified && (
                 <span className="text-muted">{t("users.account.alreadyConfirmed")}</span>
               )}
-            </FocusSafeButton>
+            </Button>
 
-            <FocusSafeButton
+            <Button
+              variant="glass"
+              fullWidth
+              icon={<KeyRound />}
+              loading={issue.isPending}
+              disabled={user.is_demo}
               onClick={() => issue.mutate()}
-              disabled={issue.isPending || user.is_demo}
-              className="w-full glass-card glass-hover flex items-center gap-2 px-3 py-2.5 rounded-lg text-xs border border-accent/40 text-accent disabled:opacity-50 transition"
+              className="border border-accent/40 text-accent"
             >
-              <KeyRound className="w-4 h-4 shrink-0" />
               <span className="flex-1 text-left">
                 {link ? t("users.account.setPasswordAgain") : t("users.account.setPassword")}
               </span>
-            </FocusSafeButton>
+            </Button>
           </div>
 
           {link && (
@@ -243,13 +250,14 @@ export default function AccountPanel({
                 <div className="flex-1 min-w-0 bg-surface border border-border rounded-lg px-3 py-2 text-2xs font-mono truncate">
                   {link.url}
                 </div>
-                <button
+                <Button
+                  variant="glass"
+                  icon={copied ? <Check /> : <Copy />}
                   onClick={copy}
-                  className="shrink-0 glass-card glass-hover inline-flex items-center gap-1.5 px-3 py-2 rounded-lg text-xs border border-accent/40 text-accent transition"
+                  className="border border-accent/40 text-accent"
                 >
-                  {copied ? <Check className="w-3.5 h-3.5" /> : <Copy className="w-3.5 h-3.5" />}
                   {copied ? t("users.account.copied") : t("users.account.copy")}
-                </button>
+                </Button>
               </div>
               <p className="text-2xs text-muted leading-relaxed">{t("users.account.linkNote")}</p>
             </div>