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/ChannelLink.tsx

@@ -1,9 +1,9 @@
 import { useTranslation } from "react-i18next";
 import { ExternalLink } from "lucide-react";
 import Avatar from "./ui/Avatar";
-import Tooltip from "./ui/Tooltip";
 import { channelYouTubeUrl } from "../lib/format";
 import { Pressable } from "./ui/Pressable";
+import { IconLink } from "./ui/LinkButton";
 
 // Avatar + channel name + "open on YouTube" link, shared by the Channel manager and the
 // discovery list (and anywhere else that lists a channel). When `onView` is given the name
@@ -47,7 +47,7 @@ export default function ChannelLink({
           }}
           // title = the full name, so a truncated fluid-column name is still readable on hover.
           title={name}
-          className="text-sm font-medium truncate hover:text-accent min-w-0"
+          className="min-h-6 min-w-0 truncate text-sm font-medium hover:text-accent pointer-coarse:min-h-(--touch-target)"
         >
           {name}
         </Pressable>
@@ -56,17 +56,15 @@ export default function ChannelLink({
           {name}
         </span>
       )}
-      <Tooltip hint={t("channels.row.openOnYouTube")}>
-        <a
-          href={ytUrl}
-          target="_blank"
-          rel="noopener noreferrer"
-          className="text-muted hover:text-accent shrink-0"
-          aria-label={t("channels.row.openOnYouTube")}
-        >
-          <ExternalLink className="w-3.5 h-3.5" />
-        </a>
-      </Tooltip>
+      <IconLink
+        href={ytUrl}
+        target="_blank"
+        rel="noopener noreferrer"
+        label={t("channels.row.openOnYouTube")}
+        className="shrink-0"
+      >
+        <ExternalLink />
+      </IconLink>
     </div>
   );
 }