Add Prompt Builder page for multi-scene prompt sequences.

Name, save, and load ordered scenes on the server; assemble copyable text with a Batch-compatible double blank line between scenes.

components/AppHeader.vue

@@ -55,6 +55,13 @@
             role="menuitem"
             @click="menuOpen = false"
           >Director</NuxtLink>
+          <NuxtLink
+            to="/prompt-builder"
+            class="block rounded-xl px-3 py-2 text-sm hover:bg-white/5 hover:text-white"
+            :class="current === 'prompt-builder' ? 'text-amber-100' : 'text-zinc-200'"
+            role="menuitem"
+            @click="menuOpen = false"
+          >Prompt Builder</NuxtLink>
           <NuxtLink
             to="/music"
             class="block rounded-xl px-3 py-2 text-sm hover:bg-white/5 hover:text-white"
@@ -131,7 +138,7 @@
 <script setup lang="ts">
 withDefaults(defineProps<{
   subtitle: string
-  current?: 'studio' | 'library' | 'director' | 'queue' | 'settings' | 'music'
+  current?: 'studio' | 'library' | 'director' | 'prompt-builder' | 'queue' | 'settings' | 'music'
   wide?: boolean
   queueCount?: number
 }>(), {

components/studio2/Bench.vue

@@ -15,6 +15,7 @@
    <div class="bench-header-right">
     <nav class="bench-nav" aria-label="Studio links">
      <NuxtLink to="/library">Library</NuxtLink>
+     <NuxtLink to="/prompt-builder">Prompt Builder</NuxtLink>
      <NuxtLink to="/queue">Queue</NuxtLink>
      <NuxtLink to="/settings">Settings</NuxtLink>
     </nav>