feat(chat): add right-click context menus on messages (M8.9)

Reusable ContextMenu.vue glass-card component positioned at cursor.
Messages get Copy, Reply, Edit (user), Regenerate (assistant), and
Branch from here options. Closes on Escape or outside click.

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

packages/app/src/components/chat/ChatMessage.vue

@@ -3,6 +3,7 @@
     class="group/msg flex animate-fade-up-fast"
     :class="isUser ? 'justify-end' : 'justify-start'"
     :style="{ animationDelay: `${index * 30}ms` }"
+    @contextmenu.prevent="openContextMenu"
   >
     <div class="relative max-w-[85%] md:max-w-[75%]">
       <!-- Action buttons (hover on desktop, always visible on touch) -->
@@ -248,12 +249,23 @@
       </div>
       </div>
     </div>
+
+    <!-- Context menu -->
+    <ContextMenu ref="contextMenuRef">
+      <ContextMenuItem v-if="isUser" @click="startEditingFromMenu">Edit</ContextMenuItem>
+      <ContextMenuItem v-if="!isUser" @click="emitRegenerate">Regenerate</ContextMenuItem>
+      <ContextMenuItem @click="emitReply">Reply</ContextMenuItem>
+      <ContextMenuItem v-if="!isUser" @click="emitBranch">Branch from here</ContextMenuItem>
+      <ContextMenuItem @click="copyContent">Copy</ContextMenuItem>
+    </ContextMenu>
   </div>
 </template>
 
 <script setup lang="ts">
 import { computed, ref, nextTick } from 'vue'
 import MarkdownIt from 'markdown-it'
+import ContextMenu from '@/components/ui/ContextMenu.vue'
+import ContextMenuItem from '@/components/ui/ContextMenuItem.vue'
 import type { Message, WebSearchResult } from '@aiui/core/types/message'
 import type { Film, Song, Podcast, Book, TVSeries, ImageItem, Place } from '@aiui/core/types/content'
 import { useContentPanel, type MagazineSection } from '@/composables/useContentPanel'
@@ -497,4 +509,36 @@ function handleBubbleClick() {
   }
   if (hasContext.value) openPanel()
 }
+
+// Context menu
+const contextMenuRef = ref<InstanceType<typeof ContextMenu> | null>(null)
+
+function openContextMenu(e: MouseEvent) {
+  contextMenuRef.value?.open(e.clientX, e.clientY)
+}
+
+function startEditingFromMenu() {
+  contextMenuRef.value?.close()
+  startEditing()
+}
+
+function emitRegenerate() {
+  contextMenuRef.value?.close()
+  emit('regenerate')
+}
+
+function emitReply() {
+  contextMenuRef.value?.close()
+  emit('reply', props.message.id, props.message.content)
+}
+
+function emitBranch() {
+  contextMenuRef.value?.close()
+  emit('branch', props.message.id)
+}
+
+function copyContent() {
+  contextMenuRef.value?.close()
+  navigator.clipboard.writeText(props.message.content).catch(() => {})
+}
 </script>

packages/app/src/components/ui/ContextMenu.vue

@@ -0,0 +1,82 @@
+<template>
+  <Teleport to="body">
+    <div
+      v-if="isOpen"
+      class="fixed inset-0 z-[9998]"
+      aria-hidden="true"
+      @click="close"
+      @contextmenu.prevent="close"
+    />
+    <Transition name="context-menu">
+      <div
+        v-if="isOpen"
+        class="fixed z-[9999] glass-card p-1.5 rounded-xl shadow-2xl animate-scale-in min-w-[140px]"
+        :style="positionStyle"
+        role="menu"
+        @click.stop
+      >
+        <slot />
+      </div>
+    </Transition>
+  </Teleport>
+</template>
+
+<script setup lang="ts">
+import { ref, computed, onMounted, onUnmounted } from 'vue'
+
+const isOpen = ref(false)
+const x = ref(0)
+const y = ref(0)
+
+const positionStyle = computed(() => {
+  // Keep menu within viewport
+  const menuWidth = 160
+  const menuHeight = 200
+  const adjustedX = Math.min(x.value, window.innerWidth - menuWidth - 8)
+  const adjustedY = Math.min(y.value, window.innerHeight - menuHeight - 8)
+  return {
+    left: `${Math.max(8, adjustedX)}px`,
+    top: `${Math.max(8, adjustedY)}px`,
+  }
+})
+
+function open(clientX: number, clientY: number) {
+  x.value = clientX
+  y.value = clientY
+  isOpen.value = true
+}
+
+function close() {
+  isOpen.value = false
+}
+
+function handleEscape(e: KeyboardEvent) {
+  if (e.key === 'Escape' && isOpen.value) {
+    close()
+  }
+}
+
+onMounted(() => {
+  document.addEventListener('keydown', handleEscape)
+})
+
+onUnmounted(() => {
+  document.removeEventListener('keydown', handleEscape)
+})
+
+defineExpose({ open, close, isOpen })
+</script>
+
+<style scoped>
+.context-menu-enter-active {
+  transition: all 0.15s cubic-bezier(0.22, 1, 0.36, 1);
+}
+.context-menu-leave-active {
+  transition: all 0.1s ease-in;
+}
+.context-menu-enter-from,
+.context-menu-leave-to {
+  opacity: 0;
+  transform: scale(0.95);
+}
+</style>

packages/app/src/components/ui/ContextMenuItem.vue

@@ -0,0 +1,25 @@
+<template>
+  <button
+    class="w-full text-left px-3 py-2 rounded-lg text-xs transition-all flex items-center gap-2"
+    :class="destructive
+      ? 'text-red-400/80 hover:text-red-400 hover:bg-white/10'
+      : 'text-white/60 hover:text-white hover:bg-white/10'"
+    role="menuitem"
+    @click="$emit('click')"
+  >
+    <slot />
+  </button>
+</template>
+
+<script setup lang="ts">
+withDefaults(
+  defineProps<{
+    destructive?: boolean
+  }>(),
+  { destructive: false }
+)
+
+defineEmits<{
+  click: []
+}>()
+</script>