Remove default layout, migrate all pages to topnav

- Add layout: 'topnav' to all 27 pages that were using default layout
- Delete app/layouts/default.vue

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

app/pages/clientarea/kyc/russia.vue

@@ -46,6 +46,7 @@
 import { CreateKycRequestRussiaDocument } from '~/composables/graphql/user/kyc-generated'
 
 definePageMeta({
+  layout: 'topnav',
   middleware: ['auth-oidc']
 })