fix(design): claim audit part 1b — whole-row switches, the field-family edge, state-layer hovers, icon links, reason-disabled controls, 24/44 targets (E28)

- F12 (owner: A): SwitchRow, the whole settings row toggles; a Config boolean toggles from its title
  and hint (a label pointed at the switch).
- F14 (owner: B): the form dropdown trigger wears the field frame (see-through, the >= 3:1 edge);
  labelled pills keep the faint edge and the accent-edge hover. DESIGN says so, with log rows.
- F6: ~15 bg-card / bg-border / opacity hovers onto the B3 state layer; a lint rule (HOVER_SWAP)
  refuses the swap, contract-tested.
- F10: bare 14px icon links onto IconLink / LinkButton; a local lint rule refuses a glyph-only <a>.
- F13: reason-disabled controls are aria-disabled (Users, Channels backfill, Discovery, Scheduler
  runs, Config tests); FocusSafeButton now swallows the click of a caller's aria-disabled; the
  Config tests say why while dirty (testDirty, HU/EN).
- F5/F11: every control measured live at 24 (mouse) and 44 (coarse) across every page; touch-target
  is a utility that wins over a caller's min-h-6; link variants carry it too; SegmentedToggle,
  Tabs, NavRail, menu rows, PriorityStepper, sliders, CheckRow, InnerInput, card links and the rest.
- F9: DismissibleChip's label reaches the chip's 24; the Combobox chips are DismissibleChips.
- F15: the "+N" / "More..." open state worded as it renders.

frontend/src/components/PlayerModal.tsx

@@ -65,6 +65,7 @@ import { Button } from "./ui/Button";
 import { IconButton } from "./ui/IconButton";
 import { Pressable } from "./ui/Pressable";
 import { SURFACE } from "./ui/surfaces";
+import { IconLink, LinkButton } from "./ui/LinkButton";
 
 // Experiment (branch experiment/inline-player): play the video in-app via the
 // YouTube IFrame Player API (not a bare embed) so we can read playback position
@@ -745,15 +746,15 @@ export default function PlayerModal({
                       ? t("player.embedDisabledBody")
                       : t("player.unavailableBody")}
                   </p>
-                  <a
+                  <LinkButton
                     href={`https://www.youtube.com/watch?v=${currentVideoId}`}
                     target="_blank"
                     rel="noreferrer"
-                    className="inline-flex h-8 items-center justify-center gap-1.5 rounded-lg px-3 text-sm font-medium state-filled touch-target"
+                    variant="primary"
+                    icon={<ExternalLink />}
                   >
-                    <ExternalLink className="size-4" />
                     {t("player.openOnYoutube")}
-                  </a>
+                  </LinkButton>
                 </div>
               </div>
             )}
@@ -875,16 +876,15 @@ export default function PlayerModal({
                     }}
                     className="font-medium hover:text-accent truncate text-left"
                   />
-                  <a
+                  <IconLink
                     href={active.channel_url}
                     target="_blank"
                     rel="noreferrer"
-                    title={t("channels.row.openOnYouTube")}
-                    aria-label={t("channels.row.openOnYouTube")}
-                    className="text-muted hover:text-accent shrink-0"
+                    label={t("channels.row.openOnYouTube")}
+                    className="shrink-0"
                   >
-                    <ExternalLink className="w-3.5 h-3.5" />
-                  </a>
+                    <ExternalLink />
+                  </IconLink>
                 </div>
               )}
               {!navigated ? (