fix(e24): the review's seven frontend defects on the Home surface

Shift+W was dead whenever anything was open. The global handler called `setPage` directly,
so the page change unmounted the player (it lives inside the module column) and that
unmount's reconcile reclaimed the entry the navigation had just pushed — the player closed
and the page snapped back. `closeThenNavigate` cannot serve here: a global key does not
know which overlay is open, or whether one is. `navigateOverOverlays` is the same fix one
step shorter — bury the live overlay entries first, so the unmount consumes the marks
instead of issuing `history.back()`.

`q.isError` had no `&& !data` guard, alone among 33 call sites and against the convention
`ui/QueryState` documents: react-query flips status to error on a failed REFETCH while
keeping the payload, and every mutation here invalidates the discover prefix, so one blip
while marking a card watched blanked a fully populated landing page.

The reroll's key rooted at "discover-pick", outside the prefix every mutation invalidates,
so a rerolled hero outlived the page: play it, finish it, and it was still the answer with
a zeroed progress bar. It now sits under the same root. A FAILED reroll also rewound the
hero to the card the page loaded with, several presses back, because a new key per press
means `keepPreviousData` (pending-only) cannot cover an error; the last resolved pick is
held instead.

The bookmark on a rail tile never updated — `VideoCard` reads `video.saved` from this
payload and keeps no optimistic state — so the star stayed empty and the next click
re-sent the same call.

The shelf reorder wrote a captured snapshot back on failure rather than re-asking the
server, which its own comment promised: two overlapping moves each reverted to their own
snapshot and settled on an order neither side held, and since `before` is the whole
payload a rollback also discarded any rail refresh that had landed meanwhile. It now
invalidates the discover PREFIX on settle, which also fixes the sibling budgets keeping
the pre-move order.

The hero/rail de-duplication matched one key, so for a Plex series — the rail row is the
show, the hero is the episode it resolves to — the same series printed twice; it now
matches both keys, as `hero.pick`'s own exclusion already did. And when the hero empties
the resume rail, the rail is hidden rather than announcing "nothing half-finished right
now" under a hero captioned "where you left off".

Ten regression tests, all mutation-checked. Three of them were rewritten after the first
mutation round showed they could not go red: two asserted before the state under test had
settled, one matched a title the Plex tile does not render.

frontend/src/App.tsx

@@ -37,6 +37,7 @@ import Toaster from "./components/ui/Toaster";
 import KeyboardHelp from "./components/ui/KeyboardHelp";
 import AppCommandPalette from "./components/AppCommandPalette";
 import { useGlobalKeymap } from "./lib/keymap";
+import { navigateOverOverlays } from "./lib/history";
 import { StateMessage } from "./components/ui/QueryState";
 import ErrorDialog from "./components/ErrorDialog";
 import VersionBanner from "./components/VersionBanner";
@@ -141,7 +142,11 @@ export default function App() {
   // Home ("mit nézzek?"). Bound only once signed in, because that is where the overlays are mounted
   // (bottom of this tree) and where the modules exist at all — see useGlobalKeymap on why binding it
   // above the signed-out branch is worse than not binding it.
-  useGlobalKeymap(!!meQuery.data, () => setPage("home"));
+  // Through `navigateOverOverlays`, because a global key can fire while an overlay is open and does
+  // not know it: the page change unmounts the player (it lives inside the module), whose reconcile
+  // then reclaimed the entry this push had just made — Shift+W over a playing video closed the
+  // player and snapped straight back to the feed.
+  useGlobalKeymap(!!meQuery.data, () => navigateOverOverlays(() => setPage("home")));
 
   // Pin this tab to whatever account it first loaded as. Without this, a tab that never picked
   // an account (it was riding the session's default) would silently swap identity when ANOTHER