fix(player): related marks survive, Restart restarts, and refused pages offer nothing to click

- Every state and Watch-later write goes through features/video/videoWrites,
  which marks the never-refetched lists (related lists, live searches) once
  the server has it; a contract test holds it. The Notification Center's
  undo, the feed's reset and the Watch-later toggles skipped it before.
- Confirmed marks are also kept apart (qk.videoMarks) and laid over the
  related rows: a Show more page landing later rebuilt them from the pages
  it read when it started, and dropped a mark made meanwhile.
- Restart on a related video starts at 0 (the session's stored position
  won before), and on the one already playing it seeks.
- The watched toggle remembers each video's mark: Back showed the opened
  video's launch-time state after a related one was marked.
- The help sheet leaves out the player's keys while a layer above it has
  them waiting.
- After a refusal a retry cannot answer, neither Show more (related) nor
  Load more (live search) is offered; a failed live-search page keeps the
  results already read and says why under them.
- The related cap message counts requests, as the cap does.

frontend/src/modules/notifications/NotificationsPanel.tsx

@@ -48,6 +48,7 @@ import { PageToolbar } from "../../components/ui/PageShell";
 import { PageMenu } from "../../components/ui/PageMenu";
 import { LoadingState, StateMessage } from "../../components/ui/QueryState";
 import { useNavigationActions } from "../../features/navigation/navigationContext";
+import { writeVideoState } from "../../features/video/videoWrites";
 import { useFilesActions } from "../files";
 import { useChannelsActions } from "../channels";
 import { useFeedFilters, useFeedFiltersActions } from "../feed";
@@ -170,8 +171,7 @@ export default function NotificationsPanel() {
     setPage("feed");
   }
   function revertState(meta: VideoHiddenMeta | VideoWatchedMeta) {
-    api
-      .setState(meta.videoId, "new")
+    writeVideoState(qc, meta.videoId, "new")
       .then(() => {
         qc.invalidateQueries({ queryKey: qk.feed() });
         qc.invalidateQueries({ queryKey: qk.feedSummary() });