fix: configure PrimeVue Aura dark theme so dialogs render

theme: 'none' meant Dialog/InputText/Select/Button had zero CSS.
Configured Aura preset with sky primary + dark mode selector.

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

frontend/nuxt.config.ts

@@ -1,3 +1,42 @@
+import Aura from '@primevue/themes/aura'
+import { definePreset } from '@primevue/themes'
+
+const WraithPreset = definePreset(Aura, {
+  semantic: {
+    primary: {
+      50: '{sky.50}',
+      100: '{sky.100}',
+      200: '{sky.200}',
+      300: '{sky.300}',
+      400: '{sky.400}',
+      500: '{sky.500}',
+      600: '{sky.600}',
+      700: '{sky.700}',
+      800: '{sky.800}',
+      900: '{sky.900}',
+      950: '{sky.950}',
+    },
+    colorScheme: {
+      dark: {
+        surface: {
+          0: '#ffffff',
+          50: '{gray.50}',
+          100: '{gray.100}',
+          200: '{gray.200}',
+          300: '{gray.300}',
+          400: '{gray.400}',
+          500: '{gray.500}',
+          600: '{gray.600}',
+          700: '{gray.700}',
+          800: '{gray.800}',
+          900: '{gray.900}',
+          950: '{gray.950}',
+        },
+      },
+    },
+  },
+})
+
 export default defineNuxtConfig({
   ssr: false,
   devtools: { enabled: false },
@@ -9,7 +48,12 @@ export default defineNuxtConfig({
   css: ['~/assets/css/main.css', '@xterm/xterm/css/xterm.css'],
   primevue: {
     options: {
-      theme: 'none',
+      theme: {
+        preset: WraithPreset,
+        options: {
+          darkModeSelector: '.dark',
+        },
+      },
     },
   },
   runtimeConfig: {