fix: code review and bugs

questions.ts

templates/components/vectordbs/python/none/context.py

templates/components/vectordbs/python/none/index.py

...s/types/simple/express/src/controllers/chat.controller.ts

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

templates/types/simple/fastapi/app/engine/index.py

...ypes/streaming/express/src/controllers/chat.controller.ts

templates/types/streaming/fastapi/README-template.md

templates/types/streaming/fastapi/app/engine/index.py

templates/types/streaming/nextjs/app/api/chat/route.ts