fix(home): shelf honours the Plex gate; hero unpins its origin; palette asks for a surprise

- A13: with Plex off, the Home shelf and the hero's comfort tier go YouTube-only like the rails
  beside them (owner's call: hide the tiles). The pins are kept; GET /pins still lists them.
- Reorder deals the listed pins into the slots they already hold, so a partial list (hidden Plex
  pins, a stale tab) no longer puts two pins on one position; repeats are ignored.
- A21: a comfort hero carries `pinned_from`, the shelf entry it was resolved from; its menu acts on
  that pin, so a pinned show's next episode offers "Unpin" instead of creating a second pin.
- B12: the palette's "Meglepetés" asks for the surprise tier (the next press leading with it); the
  rotation carries on from there.
- B13: the surprise token names the history entry it was requested for (minted by setPage's new
  `then`, after the push) and is dropped on any other entry, so a navigation that never mounted
  Home cannot replay it later.

frontend/src/components/Home.pin.dom.test.tsx

@@ -61,6 +61,7 @@ vi.mock("../lib/api", () => ({
   },
   HttpError: class extends Error {},
   DISCOVER_BUDGETS: ["short", "medium", "long", "any"],
+  HERO_TIERS: ["resume", "comfort", "surprise"],
   discoverCardKey: (c: { source: string; id: string }) => `${c.source}:${c.id}`,
 }));
 
@@ -302,6 +303,34 @@ describe("Home — the comfort shelf's context menu", () => {
     await waitFor(() => expect(removeComfortPin).toHaveBeenCalledWith(11));
   });
 
+  // A comfort hero resolved from a pinned SHOW is that show's next episode, which is not itself
+  // pinned: the menu looked the episode up, missed, and offered "Pin" under "From your shelf" —
+  // taking it created a second pin. The card now names the pin it came from, and the row acts on
+  // THAT (owner's call, 2026-09-19: "Unpin").
+  it("unpins the SHOW a comfort hero's episode was resolved from", async () => {
+    const show = {
+      ...base("ps1", "Pinned show"),
+      source: "plex",
+      kind: "show",
+      video: null,
+      pin_id: 21,
+    };
+    const episode = {
+      ...base("ps1e2", "Next episode"),
+      source: "plex",
+      kind: "episode",
+      video: null,
+      pinned_from: { source: "plex", kind: "show", id: "ps1", title: "Pinned show" },
+    };
+    discover.mockResolvedValue({ ...payload(), hero: { tier: "comfort", card: episode } });
+    comfortPins.mockResolvedValue({ items: [...shelf, show] });
+    mount();
+    fireEvent.contextMenu(await screen.findByText("Next episode"));
+    fireEvent.click(await waitFor(() => item("home.pin.remove")));
+    await waitFor(() => expect(removeComfortPin).toHaveBeenCalledWith(21));
+    expect(addComfortPin).not.toHaveBeenCalled();
+  });
+
   it("says so rather than guessing while the shelf is still loading", async () => {
     // "Not pinned" and "not known yet" must not render as the same row: the pin label is only
     // trustworthy once the shelf has answered.