feat(design): a channel's and a Plex playlist's one action list (C1) — the row's "…", Delete + undo, an action toast's 8 s floor (E28 S3e2)

- Channels: the row's full-history, hide and unsubscribe buttons become its "…" at the row end
  (useChannelActions: open, pin, YouTube, copy name / link, full history or the admin reset,
  hide with an undo toast, unsubscribe behind its danger confirm); the card layout docks the "…"
  beside the name (ChannelLayoutGrid moreKey). The admin reset's confirm now names the reset.
- Plex playlist page: a title, a show group and a season each open the page's one row menu (a
  title's is its usePlexCardActions list plus the removal); no X at rest; removals take an undo
  toast whose Undo puts every row back at its own index in one request (bulk add `positions`);
  j/k walk the visible rows, Delete removes the walked one; rename and delete in the header's "…".
- notify: a toast with an action lives at least 8 s (the owner's call), whatever the toast setting.

frontend/src/components/channelCells.tsx

@@ -1,10 +1,9 @@
 import { useTranslation } from "react-i18next";
-import { Check, Eye, EyeOff, History, UserMinus } from "lucide-react";
+import { Check } from "lucide-react";
 import type { ManagedChannel } from "../lib/api";
 import { formatNumber } from "../lib/format";
 import Tooltip from "./ui/Tooltip";
 import { isFullySynced } from "./channelSync";
-import { IconButton } from "./ui/IconButton";
 
 // The Channels-manager cells that are components in their own right (they read i18n), split out of
 // channelColumns so that file holds only the column factory and its predicates (Fast Refresh).
@@ -29,77 +28,3 @@ export function StoredCell({ c }: { c: ManagedChannel }) {
     </span>
   );
 }
-
-export function ActionsCell({
-  c,
-  isAdmin,
-  canWrite,
-  onHide,
-  onDeep,
-  onReset,
-  onUnsubscribe,
-}: {
-  c: ManagedChannel;
-  isAdmin: boolean;
-  canWrite: boolean;
-  onHide: () => void;
-  onDeep: () => void;
-  onReset: () => void;
-  onUnsubscribe: () => void;
-}) {
-  const { t } = useTranslation();
-  // Admins get a "reset" trigger that re-fetches the channel from scratch regardless of
-  // state — always actionable. Regular users get the per-user "request full history" opt-in,
-  // which only applies until the back-catalog is in (or already coming for everyone).
-  const done = c.backfill_done;
-  const requested = !done && c.deep_requested;
-  const optInActionable = !done && !c.deep_in_queue;
-  const backfillHint = isAdmin
-    ? t("channels.row.resetHint")
-    : c.deep_in_queue
-      ? t("channels.row.queuedByOtherHint")
-      : requested
-        ? t("channels.row.queuedRequestedHint")
-        : done
-          ? t("channels.row.fullHint")
-          : t("channels.row.backfillThisHint");
-  const enabled = isAdmin || optInActionable;
-  return (
-    <div className="inline-flex items-center gap-2">
-      {/* Unavailable with a reason (queued by someone else, already full): aria-disabled keeps it
-          focusable, so the hint that says why is reachable by keyboard too. */}
-      <Tooltip hint={backfillHint} always={!enabled}>
-        <IconButton
-          onClick={isAdmin ? onReset : onDeep}
-          aria-disabled={!enabled}
-          variant={requested ? "ghost-accent" : "ghost"}
-          label={isAdmin ? t("channels.row.resetBackfill") : t("channels.row.backfillThis")}
-          noTitle
-        >
-          <History />
-        </IconButton>
-      </Tooltip>
-      <Tooltip hint={c.hidden ? t("channels.row.hiddenHint") : t("channels.row.hideHint")}>
-        <IconButton
-          onClick={onHide}
-          label={c.hidden ? t("channels.row.unhide") : t("channels.row.hideFromFeed")}
-          noTitle
-        >
-          {c.hidden ? <EyeOff /> : <Eye />}
-        </IconButton>
-      </Tooltip>
-      {canWrite && (
-        <Tooltip hint={t("channels.row.unsubscribeHint")}>
-          <IconButton
-            variant="danger"
-            onClick={onUnsubscribe}
-            label={t("channels.row.unsubscribeOnYoutube")}
-            noTitle
-          >
-            <UserMinus />
-          </IconButton>
-        </Tooltip>
-      )}
-    </div>
-  );
-}