feat: integrate llamaindex chat-ui (#399)

.changeset/nice-garlics-repeat.md

...es/types/streaming/nextjs/app/components/chat-section.tsx

...pes/streaming/nextjs/app/components/ui/README-template.md

.../streaming/nextjs/app/components/ui/chat/chat-actions.tsx

...s/streaming/nextjs/app/components/ui/chat/chat-avatar.tsx

...es/streaming/nextjs/app/components/ui/chat/chat-input.tsx

...ng/nextjs/app/components/ui/chat/chat-message-content.tsx

...app/components/ui/chat/chat-message/chat-agent-events.tsx

...extjs/app/components/ui/chat/chat-message/chat-events.tsx

...nextjs/app/components/ui/chat/chat-message/chat-files.tsx

...nextjs/app/components/ui/chat/chat-message/chat-image.tsx

...xtjs/app/components/ui/chat/chat-message/chat-sources.tsx

...mponents/ui/chat/chat-message/chat-suggestedQuestions.tsx

...nextjs/app/components/ui/chat/chat-message/chat-tools.tsx

.../nextjs/app/components/ui/chat/chat-message/codeblock.tsx

...ming/nextjs/app/components/ui/chat/chat-message/index.tsx

...g/nextjs/app/components/ui/chat/chat-message/markdown.tsx

...streaming/nextjs/app/components/ui/chat/chat-messages.tsx

.../streaming/nextjs/app/components/ui/chat/chat-starter.tsx

...streaming/nextjs/app/components/ui/chat/chat.interface.ts