feat: display sources in chat messages (#45)

helpers/env-variables.ts

package.json

pnpm-lock.yaml

templates/types/streaming/express/package.json

...es/streaming/express/src/controllers/llamaindex-stream.ts

templates/types/streaming/fastapi/app/api/routers/chat.py

...ypes/streaming/fastapi/app/api/routers/vercel_response.py

.../types/streaming/nextjs/app/api/chat/llamaindex-stream.ts

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

templates/types/streaming/nextjs/app/components/transform.ts

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

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

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

...es/types/streaming/nextjs/app/components/ui/chat/index.ts

...s/types/streaming/nextjs/app/components/ui/hover-card.tsx

templates/types/streaming/nextjs/package.json