fix: replace invalid TanStack Router search casts with typed defaults

Newer TanStack Router enforces strict types on search params — 'search: {} as Record<string, unknown>' no longer satisfies routes with validateSearch. Replace all occurrences with the correct search shape for each destination route (pagination defaults for list routes, tab/field defaults for detail routes).

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

packages/admin/src/routes/_authenticated/index.tsx

@@ -2,6 +2,6 @@ import { createFileRoute, redirect } from '@tanstack/react-router'
 
 export const Route = createFileRoute('/_authenticated/')({
   beforeLoad: () => {
-    throw redirect({ to: '/accounts', search: {} as Record<string, unknown> })
+    throw redirect({ to: '/accounts', search: { page: 1, limit: 25, q: undefined, sort: undefined, order: 'asc' as const } })
   },
 })