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/channelColumns.tsx

@@ -1,4 +1,4 @@
-import type { ComponentProps } from "react";
+import type { ComponentProps, ReactNode } from "react";
 import type { TFunction } from "i18next";
 import { NO_TAG_SENTINEL, type ManagedChannel } from "../lib/api";
 import { formatCountOrDash, formatTotalHours, relativeTime } from "../lib/format";
@@ -7,7 +7,7 @@ import { PriorityStepper } from "./ui/PriorityStepper";
 import ChannelLink from "./ChannelLink";
 import AboutCell from "./AboutCell";
 import { ChannelTagsControl, type SuggestedTag } from "./ChannelTags";
-import { ActionsCell, StoredCell } from "./channelCells";
+import { StoredCell } from "./channelCells";
 import { isFullySynced } from "./channelSync";
 
 /** The shared "subscribers" DataTable column (right-aligned, sortable, em-dash for null) — identical
@@ -49,16 +49,12 @@ export function tagsColumnTest(c: ManagedChannel, values: string[]): boolean {
  * column block lives outside the page component (its cell components are in channelCells). */
 export interface ChannelColumnDeps {
   t: TFunction;
-  isAdmin: boolean;
-  canWrite: boolean;
   prioOptions: { value: string; label: string }[];
   userTags: ComponentProps<typeof ChannelTagsControl>["userTags"];
   bumpPriority: (id: string, delta: number) => void;
   setPriority: (id: string, value: number) => void;
-  onHide: (c: ManagedChannel) => void;
-  onDeep: (c: ManagedChannel) => void;
-  onReset: (c: ManagedChannel) => void;
-  onUnsub: (c: ManagedChannel) => void;
+  /** The row's "…" — the door to the channel's one action list (`useChannelActions`). */
+  more: (c: ManagedChannel) => ReactNode;
   onView: (c: ManagedChannel) => void;
   toggleTag: (channelId: string, tagId: number, hasTag: boolean) => void;
   createAndAttachTag: (channelId: string, name: string) => void;
@@ -72,16 +68,11 @@ export interface ChannelColumnDeps {
 export function buildChannelColumns(deps: ChannelColumnDeps): Column<ManagedChannel>[] {
   const {
     t,
-    isAdmin,
-    canWrite,
     prioOptions,
     userTags,
     bumpPriority,
     setPriority,
-    onHide,
-    onDeep,
-    onReset,
-    onUnsub,
+    more,
     onView,
     toggleTag,
     createAndAttachTag,
@@ -109,25 +100,6 @@ export function buildChannelColumns(deps: ChannelColumnDeps): Column<ManagedChan
         />
       ),
     },
-    {
-      key: "actions",
-      header: t("channels.cols.actions"),
-      align: "left",
-      nowrap: true,
-      width: "5.5rem",
-      cardLabel: false,
-      render: (c) => (
-        <ActionsCell
-          c={c}
-          isAdmin={isAdmin}
-          canWrite={canWrite}
-          onHide={() => onHide(c)}
-          onDeep={() => onDeep(c)}
-          onReset={() => onReset(c)}
-          onUnsubscribe={() => onUnsub(c)}
-        />
-      ),
-    },
     {
       key: "channel",
       header: t("channels.cols.channel"),
@@ -217,5 +189,17 @@ export function buildChannelColumns(deps: ChannelColumnDeps): Column<ManagedChan
         />
       ),
     },
+    {
+      key: "actions",
+      header: "",
+      align: "right",
+      // Room for the "…" at 44px on touch (`.touch-target`), not just its 28px under a mouse.
+      width: "3.25rem",
+      nowrap: true,
+      cardLabel: false,
+      // The row's full-history, hide and unsubscribe buttons went into the menu (E28 C1): the row
+      // keeps what is read or tuned all the time — priority, tags, the ✓ — and ends in its "…".
+      render: more,
+    },
   ];
 }