refactor(frontend): read the panel's navigation from one route manifest (#6922)

The router, the sidebar, the page titles and the command palette each kept
their own list of the panel's pages, so a page added to one could go
missing from another without any test noticing. They all read
src/routes/panelRoutes.tsx now, and a contract test holds the manifest to
the router, the translation bundle and the palette keywords.

The unused useZodForm helper goes, and CONTRIBUTING, frontend/CLAUDE.md and
the frontend README describe the useForm + rhfZodValidate pattern the
panel's forms actually use.

frontend/src/hooks/usePageTitle.ts

@@ -2,27 +2,14 @@ import { useEffect } from 'react';
 import { useLocation } from 'react-router';
 import { useTranslation } from 'react-i18next';
 
-const TITLE_KEYS: Record<string, string> = {
-  '/': 'menu.dashboard',
-  '/inbounds': 'menu.inbounds',
-  '/clients': 'menu.clients',
-  '/groups': 'menu.groups',
-  '/nodes': 'menu.nodes',
-  '/hosts': 'menu.hosts',
-  '/settings': 'menu.settings',
-  '/xray': 'menu.xray',
-  '/outbound': 'menu.outbounds',
-  '/routing': 'menu.routing',
-  '/api-docs': 'menu.apiDocs',
-  '/sponsors': 'menu.sponsors',
-};
+import { PANEL_TITLE_KEYS } from '@/routes/panelRoutes';
 
 export function usePageTitle() {
   const { pathname } = useLocation();
   const { t } = useTranslation();
 
   useEffect(() => {
-    const key = TITLE_KEYS[pathname];
+    const key = PANEL_TITLE_KEYS[pathname];
     const title = key ? t(key) : '3X-UI';
     const host = window.location.hostname;
     document.title = host ? `${host} - ${title}` : title;