feat(code): add Esc to exit code mode, project indicator pill, design token context

- Escape key exits code mode on desktop (T14)
- Show active project name pill near chat input when in code mode (T15)
- Inject selected design tokens, files, and open file content into AI
  system prompt when in code mode (T16)

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

packages/app/src/composables/useAI.ts

@@ -6,6 +6,7 @@ import type { ImageAttachment } from '@aiui/core/types/message'
 import { usePersonaStore } from '@/stores/personas'
 import { useMemoryStore } from '@/stores/memory'
 import { useArchy } from '@/composables/useArchy'
+import { useCodeContext } from '@/composables/useCodeContext'
 
 type Provider = 'claude' | 'openrouter' | 'mock'
 
@@ -350,6 +351,28 @@ function buildSystemPrompt(chatStore: ReturnType<typeof useChatStore>): string {
   const archy = useArchy()
   prompt += archy.buildArchyContext()
 
+  // Append code context when in code mode
+  const code = useCodeContext()
+  if (code.isCodeMode.value) {
+    const sections: string[] = []
+    if (code.activeProject.value) {
+      sections.push(`**Active project:** ${code.activeProject.value.name} (${code.activeProject.value.language ?? 'Unknown'})`)
+    }
+    if (code.selectedDesignTokens.value.length > 0) {
+      sections.push(`**Selected design tokens:** ${code.selectedDesignTokens.value.join(', ')}`)
+    }
+    if (code.selectedFiles.value.length > 0) {
+      sections.push(`**Selected files:** ${code.selectedFiles.value.join(', ')}`)
+    }
+    if (code.activeFileContent.value && code.activeFile.value) {
+      const content = code.activeFileContent.value.slice(0, 2000)
+      sections.push(`**Open file (${code.activeFile.value}):**\n\`\`\`${code.activeFileLanguage.value}\n${content}\n\`\`\``)
+    }
+    if (sections.length > 0) {
+      prompt += `\n\n**Code Context:**\n${sections.join('\n')}`
+    }
+  }
+
   return prompt
 }