feat: add 404 catch-all route with NotFound view

Unmatched URLs now show a glass-card 404 page with a link back
to the dashboard instead of a blank page.

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

neode-ui/src/router/index.ts

@@ -185,6 +185,11 @@ const router = createRouter({
         },
       ],
     },
+    {
+      path: '/:pathMatch(.*)*',
+      name: 'not-found',
+      component: () => import('../views/NotFound.vue'),
+    },
   ],
 })
 

neode-ui/src/views/NotFound.vue

@@ -0,0 +1,15 @@
+<script setup lang="ts">
+import { RouterLink } from 'vue-router'
+</script>
+
+<template>
+  <div class="min-h-screen flex items-center justify-center px-4">
+    <div class="glass-card px-8 py-10 text-center max-w-md">
+      <h1 class="text-6xl font-bold text-white/30 mb-4">404</h1>
+      <p class="text-lg text-white/70 mb-6">Page not found</p>
+      <RouterLink to="/dashboard" class="glass-button inline-block px-6 py-3">
+        Back to Dashboard
+      </RouterLink>
+    </div>
+  </div>
+</template>