sections are paths, not a query string

The admin declares its routes in the manifest, so /fofos-admin/layout/header and
/fofos-admin/pages/home are real URLs. One reader takes the two segments after
the mount; links carry no query string at all, so nothing leaks between
sections.

What stays in the query is how you are looking — device, tab, view — rather than
at what.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

web/sections/PageBuilderPanel.tsx

@@ -1,5 +1,5 @@
 import { useCallback, useEffect, useRef, useState } from 'react';
-import { useSearchParams } from 'react-router';
+import { useNav } from '../routes';
 import { useClient } from 'hooks/useClient';
 import { readableError } from '../errors';
 import { SitePreview, useDevPort } from '../SitePreview';
@@ -57,8 +57,7 @@ export const PageBuilderPanel = () => {
   const clientRef = useRef(client);
   clientRef.current = client;
 
-  const [params] = useSearchParams();
-  const slug = params.get('page');
+  const { item: slug } = useNav();
 
   const devPort = useDevPort();
   const { pages, announce } = usePages();