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/scheduler/Scheduler.tsx

@@ -47,6 +47,7 @@ import { jobFailureText, jobResultText } from "../../lib/jobResult";
 import { StatusDot, type DotKey } from "../activity";
 import { useNavigationActions } from "../../features/navigation/navigationContext";
 import { urlWithParams } from "../../lib/urlState";
+import { activityParamUpdates, DEFAULT_ACTIVITY_STATE } from "../../lib/activityUrlState";
 
 const POLL_MS = 4000;
 // While any job is running, poll faster so short scheduled runs aren't missed between ticks.
@@ -164,7 +165,10 @@ function HistoryButton({ job }: { job: string }) {
             window.history.replaceState(
               window.history.state,
               "",
-              urlWithParams({ page: "activity", rjob: job }),
+              urlWithParams({
+                page: "activity",
+                ...activityParamUpdates({ ...DEFAULT_ACTIVITY_STATE, job }),
+              }),
             ),
           )
         }