feat: support anthropic and gemini model providers and update to LITS 0.3.3 (#63)

.changeset/lovely-papayas-exist.md

.changeset/ninety-clocks-ring.md

helpers/env-variables.ts

helpers/index.ts

helpers/providers/anthropic.ts

helpers/providers/gemini.ts

helpers/providers/index.ts

helpers/providers/ollama.ts

helpers/providers/openai.ts

helpers/python.ts

helpers/types.ts

questions.ts

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

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

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

templates/types/streaming/express/package.json

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

...ypes/streaming/express/src/controllers/engine/settings.ts

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

templates/types/streaming/fastapi/app/settings.py