Add @openuidev/vue-lang — Vue 3 runtime adapter

[dc-riskhub]

Summary

• Adds @openuidev/vue-lang package — Vue 3.5+ runtime adapter for OpenUI, following the identical pattern established by svelte-lang
• Adds vue-chat example — full Nuxt 3 chat app with Vercel AI SDK, mirroring svelte-chat
• Addresses #318 (comment): "Vue renderer would be next"

@openuidev/vue-lang — Runtime Adapter

File	Purpose
library.ts	Narrows ComponentRenderProps to VNode, wraps coreDefineComponent/coreCreateLibrary
Renderer.vue	Parses OpenUI Lang, manages form state, renders component tree via h()
RenderNode.vue	Dynamic <component :is> with onErrorCaptured error boundary
context.ts	provide/inject with typed InjectionKey symbols, 8 composables
validation.ts	Form validation via reactive() (mirrors svelte-lang's $state)
index.ts	Full public API mirroring svelte-lang's export structure

vue-chat — Example App

Full Nuxt 3 chat application using the Vercel AI SDK (@ai-sdk/vue Chat class + streamText):

• 5 OpenUI components: TextContent, Button, Card, Stack, Chart (Chart.js)
• API route (/api/chat): streamText with tool support (weather, stocks, calculator, web search)
• Streaming UI: real-time message rendering with tool call indicators (spinner → checkmark)
• Welcome screen with conversation starters
• System prompt generated via scripts/generate-prompt.mjs

Architecture

Same pipeline as svelte-chat:

1. User sends message → Chat.sendMessage() (Vercel AI SDK)
2. Server streams response via streamText().toUIMessageStreamResponse()
3. Client parses message parts → AssistantMessage extracts text content
4. Renderer from vue-lang parses OpenUI Lang → renders Vue component tree
5. Button clicks → triggerAction → BuiltinActionType.ContinueConversation

Pipeline parity with react-lang and svelte-lang

• Same createParser(library.toJSONSchema()) from lang-core
• Same component resolution: library.components[typeName] → pass props + renderNode
• Same form state management: getFieldValue/setFieldValue/triggerAction
• Same callback signatures: onAction, onStateUpdate, onParseResult
• Error boundary preserves last valid render (matches React behavior)

Test plan

vue-lang

• 30 tests passing (library: 8, renderer: 7, validation: 15)
• pnpm --filter @openuidev/vue-lang build — Vite library mode (6.27 kB)
• pnpm --filter @openuidev/vue-lang test — Vitest with jsdom

vue-chat

• Welcome screen renders with 4 conversation starters
• API route responds with Vercel AI SDK streaming protocol
• Tool definitions loaded (get_weather, get_stock_price, calculate, search_web)
• pnpm install clean in monorepo context
• End-to-end with OpenAI API key (requires OPENAI_API_KEY in .env)