fix(ui): focus, paging and state that a key or a finger can reach

- A key landing on a side panel's tab steps into the card it peeks open, not onto the hidden tab.
- The Channels cards keep their status / pager row at the list's end while the band is folded.
- A menu row's note shows on an enabled row too: the download state under 'Download…', not a title.
- A removal chip hands the focus to its neighbour before it goes, for every caller (the feed's and
  Plex's active filters); the hidden-filter cue's own copy is gone.
- Back to a spot within a page's end spacer lands at the page's end, not its top.
- A running push / revert is tracked per list: another list's push is no longer refused unseen.

frontend/src/components/ui/ActionMenu.dom.test.tsx

@@ -42,16 +42,20 @@ describe("ActionMenu", () => {
 
   // floating-ui never computes a position in jsdom, so the surface stays visibility:hidden; the items
   // are in the DOM but the a11y tree treats them as hidden — hence `{ hidden: true }` on role queries.
-  it("says why a disabled row is off, under its label — and only on a disabled row", () => {
+  it("says under its label why a disabled row is off, and what an enabled one opens stands at", () => {
     // A `title` on a disabled row reached nobody: a disabled button fires no pointer events and
-    // roving focus skips it. The reason is visible text now, undimmed so it can be read.
+    // roving focus skips it. The reason is visible text now, undimmed so it can be read. An enabled
+    // row's state ("Downloaded" under "Download…") is the same line: a `title` shows to a resting
+    // mouse only, never to a key or a finger (round 2, F5).
     renderMenu([
       { id: "move", label: "Move to", onSelect: vi.fn(), disabled: true, note: "No other list" },
-      { id: "sync", label: "Sync", onSelect: vi.fn(), note: "never shown" },
+      { id: "dl", label: "Download…", onSelect: vi.fn(), note: "Downloaded" },
+      { id: "sync", label: "Sync", onSelect: vi.fn() },
     ]);
     fireEvent.click(screen.getByRole("button", { name: "Catalog actions" }));
-    const [move, sync] = screen.getAllByRole("menuitem", { hidden: true });
+    const [move, dl, sync] = screen.getAllByRole("menuitem", { hidden: true });
     expect(move!.textContent).toBe("Move toNo other list");
+    expect(dl!.textContent).toBe("Download…Downloaded");
     expect(sync!.textContent).toBe("Sync");
     const note = screen.getByText("No other list");
     expect(note.closest(".opacity-50")).toBeNull();