feat: Add publisher agent, merge code with streaming template (#324)

templates/types/multiagent/fastapi/app/api/routers/upload.py

templates/types/multiagent/fastapi/app/config.py

...tes/types/multiagent/fastapi/app/examples/orchestrator.py

...lates/types/multiagent/fastapi/app/examples/researcher.py

templates/types/multiagent/fastapi/app/observability.py

templates/types/multiagent/fastapi/app/utils.py

templates/types/multiagent/fastapi/gitignore

templates/types/multiagent/fastapi/main.py

templates/types/multiagent/fastapi/pyproject.toml

templates/types/streaming/express/package.json

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

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

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

templates/types/streaming/nextjs/package.json