feat: support agent in typescript templates (#5)

helpers/tools.ts

helpers/typescript.ts

questions.ts

templates/components/engines/typescript/agent/chat.ts

templates/components/engines/typescript/chat/chat.ts

templates/components/vectordbs/typescript/none/index.ts

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

...lates/types/simple/express/src/controllers/engine/chat.ts

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

...es/types/streaming/express/src/controllers/engine/chat.ts

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

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

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

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