feat(app): add WGRplane web UI and backend features

- Add Vue 3 frontend with glassmorphism design (Tailwind CSS)
- Add Go backend handlers: auth, webhooks, stats, scheduler, validation
- Add i18n support (EN, ID, ZH)
- Add Swagger docs and API handlers
- Add nftables integration and plugins support
- Remove deprecated go.mod (migrated to wgrplane)

app/frontend/src/components/glass/GlassToggle.vue

@@ -1,9 +1,9 @@
 <template>
-  <button
-    class="relative w-12 h-6 rounded-full transition-colors"
-    :class="modelValue ? 'bg-blue-500' : 'bg-gray-600'"
-    @click="$emit('update:modelValue', !modelValue)"
-  >
+<button
+  class="relative w-12 h-6 rounded-full transition-colors"
+  :class="modelValue ? 'bg-blue-500' : 'dark:bg-gray-600 bg-gray-300'"
+  @click="$emit('update:modelValue', !modelValue)"
+>
     <span
       class="absolute top-1 left-1 w-4 h-4 bg-white rounded-full transition-transform"
       :class="modelValue ? 'translate-x-6' : ''"