feat(nav): tabs, list views and name searches are named in the address

Settings, Configuration and Users name their tab (stab/cfgtab/utab); a link's tab wins and a tab pre-selected
while its page is on screen now switches it. A playlist's sort, filters and grouping (plsort/plf/plgroup), the
Files sort (fsort, always written) and the name searches of Channels, Files, Playlists and Plex (cq/fq/plq/pq+pqf)
reopen from the address; the searches are written once the typing pauses.

frontend/src/lib/channelsUrlState.dom.test.ts

@@ -1,7 +1,7 @@
 // @vitest-environment jsdom
 //
-// The Channels-manager content state (active tab + column sort + the column-filter map) round-trips
-// through namespaced URL keys (ctab/csort/cf) so a manager view is shareable, the plexUrlState
+// The Channels-manager content state (active tab + column sort + the column-filter map + the name
+// search) round-trips through namespaced URL keys (ctab/csort/cf/cq) so a manager view is shareable, the plexUrlState
 // analogue. `cf` carries the mixed scalar/array FilterMap as a JSON blob.
 import { describe, expect, it } from "vitest";
 import {
@@ -20,7 +20,7 @@ const RICH_FILTERS: FilterMap = {
   tags: ["12", "34"],
 };
 
-const BASE: ChannelsUrlState = { view: "subscribed", sort: null, filters: {} };
+const BASE: ChannelsUrlState = { view: "subscribed", sort: null, filters: {}, search: "" };
 
 // Apply an updates delta onto a base URLSearchParams the way urlWithParams would (null deletes).
 function applyUpdates(updates: Record<string, string | null>): URLSearchParams {
@@ -32,12 +32,16 @@ function applyUpdates(updates: Record<string, string | null>): URLSearchParams {
 }
 
 describe("channelsParamUpdates", () => {
+  it("writes no search for a blank one", () => {
+    expect(channelsParamUpdates({ ...BASE, search: "  " }).cq).toBeNull();
+  });
+
   it("emits nothing for the all-default state", () => {
-    expect(channelsParamUpdates(BASE)).toEqual({ ctab: null, csort: null, cf: null });
+    expect(channelsParamUpdates(BASE)).toEqual({ ctab: null, csort: null, cf: null, cq: null });
   });
 
   it("clears every key when passed null (off-manager page)", () => {
-    expect(channelsParamUpdates(null)).toEqual({ ctab: null, csort: null, cf: null });
+    expect(channelsParamUpdates(null)).toEqual({ ctab: null, csort: null, cf: null, cq: null });
   });
 
   it("emits only non-default keys", () => {
@@ -45,16 +49,16 @@ describe("channelsParamUpdates", () => {
       view: "hidden",
       sort: { key: "subscribers", dir: "desc" },
       filters: { sync: "fully" },
+      search: "tom",
     });
     expect(u.ctab).toBe("hidden");
     expect(u.csort).toBe("subscribers:desc");
     expect(u.cf).toBe(JSON.stringify({ sync: "fully" }));
+    expect(u.cq).toBe("tom");
   });
 
   it("drops empty filter entries so a cleared funnel emits no cf", () => {
-    expect(
-      channelsParamUpdates({ view: "subscribed", sort: null, filters: { tags: [], sync: "" } }).cf,
-    ).toBeNull();
+    expect(channelsParamUpdates({ ...BASE, filters: { tags: [], sync: "" } }).cf).toBeNull();
   });
 });
 
@@ -64,12 +68,14 @@ describe("round-trip", () => {
       view: "blocked",
       sort: { key: "priority", dir: "asc" },
       filters: RICH_FILTERS,
+      search: "jazz",
     };
     const params = applyUpdates(channelsParamUpdates(state));
     const back = channelsParamsToState(params, BASE);
     expect(back.view).toBe("blocked");
     expect(back.sort).toEqual({ key: "priority", dir: "asc" });
     expect(back.filters).toEqual(RICH_FILTERS);
+    expect(back.search).toBe("jazz");
     // the array shape survives the JSON round-trip, not collapsed to a scalar
     expect(Array.isArray(back.filters.tags)).toBe(true);
   });
@@ -80,6 +86,7 @@ describe("round-trip", () => {
       view: "discovery",
       sort: null,
       filters: { sync: "needsFull" },
+      search: "",
     });
     expect(back.view).toBe("discovery"); // from base, no ctab
     expect(back.filters).toEqual({ sync: "needsFull" }); // from base, no cf
@@ -88,7 +95,7 @@ describe("round-trip", () => {
 
   it("ignores an out-of-vocabulary tab / bad sort / corrupt cf and falls back to base", () => {
     const params = new URLSearchParams("ctab=bogus&csort=key:sideways&cf=notjson");
-    const back = channelsParamsToState(params, { view: "subscribed", sort: null, filters: {} });
+    const back = channelsParamsToState(params, BASE);
     expect(back.view).toBe("subscribed"); // bogus tab → base
     expect(back.sort).toBeNull(); // bad dir → parseSortState null → base (null)
     expect(back.filters).toEqual({}); // corrupt cf → decodeFilters heals to empty