fix(nav): a linked player, file and search survive what the app does by itself (review round 2)

- Playlists: a link over a playlist the account does not hold plays alone; the rail's own
  fallback no longer counts as a pick that gives the player up.
- The linked opener opens or clears nothing once the address names another player, and stops
  looking (and fetching its row) once it settled.
- Files: a list the server's cap cut — the sorted or searched one too — keeps the link, with a
  notice of its own (EN/HU).
- History: an in-place view rewrite (search refine, count, channel to channel, sub-view)
  drops a reloaded entry's overlay marks (replaceView); a landing on a channel opened from a
  search keeps the search; the Feed press on a search opens the plain feed.
- Files/Playlists: an emptied search is written at once.
- Client log: plf/cf (column text filters) are typed keys; the shell has none of its own.
- Contract: writers outside lib/ take a literal or a lib/ function's result; every URL key is
  sorted typed or not; the writer regexes are held by a fixture; sub-views named; the bookmark
  net reads page tags.
- Feed defaults in one constant; one live-search queue helper; Scheduler writes through the
  Activity codec; notRun copy (EN/HU) names Forward and a plain "Search YouTube" button.

frontend/src/modules/files/Files.menu.dom.test.tsx

@@ -170,8 +170,11 @@ const YT = folder(1, { source_key: "youtube" });
 const OWN = folder(2, { kind: "own", name: "Cimboráknak", retention_days: null });
 const HUB = folder(4, { kind: "hub", retention_days: null, count: 0 });
 
-afterEach(() => {
+afterEach(async () => {
   cleanup();
+  // A viewer the cleanup closed steps the history back: jsdom lands that traversal a few tasks later,
+  // and on whatever case is current by then. Let it land here, before the address is reset.
+  for (let i = 0; i < 5; i++) await new Promise((r) => setTimeout(r, 0));
   vi.restoreAllMocks();
   // The page names its sort in the address: one case's sort must not open the next.
   window.history.replaceState(null, "", "/");
@@ -813,15 +816,30 @@ describe("Files · a file the address names", () => {
   // A list the cap cut cannot tell a deleted file from one beyond its end: it says the file is not
   // among the ones listed, and keeps the link.
   it("past the cap with no search or sort to widen it, says it is not listed and keeps the link", async () => {
-    // The case before closed a viewer: its step back lands a moment later, on whatever is current.
-    await new Promise((r) => setTimeout(r, 30));
     window.history.replaceState(null, "", "/?page=files&fsort=none&fview=9999");
     mocks.files = Array.from({ length: FILES_LIST_CAP }, (_, i) => file(i + 1));
     mocks.folders = [YT];
     mount();
     await waitFor(() =>
       expect(mocks.notify).toHaveBeenCalledWith(
-        expect.objectContaining({ level: "info", message: "files.arrival.notListed" }),
+        expect.objectContaining({ level: "info", message: "files.linkedNotListed" }),
+      ),
+    );
+    expect(mocks.notify).not.toHaveBeenCalledWith(
+      expect.objectContaining({ message: "files.linkedGone" }),
+    );
+    expect(here().get("fview")).toBe("9999");
+  }, 30_000); // a full page of FILES_LIST_CAP rows
+
+  it("past the cap, the server's sorted list cut too: not listed, and the link stays", async () => {
+    window.history.replaceState(null, "", "/?page=files&fsort=name:asc&fview=9999");
+    mocks.files = Array.from({ length: FILES_LIST_CAP }, (_, i) => file(i + 1));
+    mocks.searched = Array.from({ length: FILES_LIST_CAP }, (_, i) => file(i + 1));
+    mocks.folders = [YT];
+    mount();
+    await waitFor(() =>
+      expect(mocks.notify).toHaveBeenCalledWith(
+        expect.objectContaining({ level: "info", message: "files.linkedNotListed" }),
       ),
     );
     expect(mocks.notify).not.toHaveBeenCalledWith(