refactor: move router config to stx.config.ts, remove @stxRouter directive

Router container is now configured via stx.config.ts router.container
instead of @stxRouter('main') directive in the layout. The framework
injects the router and its config automatically.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: glennmichael123

packages/devtools/pages/layouts/default.stx

@@ -73,7 +73,6 @@
 </div>
 
 @stack('scripts')
-@stxRouter('main')
 
 <style>
   .sidebar.collapsed { width: 56px !important; }

packages/devtools/stx.config.ts

@@ -20,5 +20,8 @@ export default {
       bodyClass: 'bg-[#0a0a0f] text-zinc-50 leading-relaxed min-h-screen',
     },
   },
+  router: {
+    container: 'main',
+  },
   apiRoutes,
 }