fix(nav): the address follows the view through overlays, reloads and Back (review round 1)

- A URL mirror names the view again on every entry Back or Forward lands on, so a change made
  under a dialog, a drawer or a sub-view is not undone by the next reload.
- A view pushed from the entry a reload under a dialog started from no longer inherits its overlay
  mark; a reload under two overlays closes onto the page in one step.
- The linked player reopens over a live search, gives itself up when its list moves first, and
  plays alone over an emptied playlist; a capped Files list keeps the link it cannot resolve.
- The Feed press over a channel ends the search; leaving a search ends its asked mark; Files and
  Playlists searches end with their page; the feed always names its view and debounces its search.
- Search-box keys are declared per module and kept out of the client log below TRACE.
- Writers outside lib/ go through codecs; the URL contract scans computed keys, overlay writers and
  two-line reads, and holds every page to a bookmark round trip (Config, Activity, Playlists and the
  Files sort and viewer added).

frontend/src/modules/users/AdminUsers.tsx

@@ -27,7 +27,7 @@ import { displayName } from "../../lib/api/account";
 import { notify } from "../../lib/notifications";
 import { formatDateTime, relativeTime } from "../../lib/format";
 import { invalidateUserAccess } from "../../lib/adminUsers";
-import { ADMIN_USERS_TAB_KEY, USERS_TAB_URL_KEY } from "../../lib/adminUsersTab";
+import { ADMIN_USERS_TAB_KEY, USERS_TAB_URL_KEY, usersTabParams } from "../../lib/adminUsersTab";
 import { Badge } from "../../components/ui/Badge";
 import { Button } from "../../components/ui/Button";
 import { IconButton } from "../../components/ui/IconButton";
@@ -89,7 +89,7 @@ export default function AdminUsers() {
   ];
   const active = tabs.some((x) => x.id === tab) ? tab : "roles";
   // The address names the tab on screen (always: see SettingsPanel).
-  useUrlMirror({ [USERS_TAB_URL_KEY]: active });
+  useUrlMirror(usersTabParams(active));
   return (
     <>
       {/* The tab bar is fixed chrome; the tab content scrolls under it. */}