feat: support mistral as llm and embedding (#155)

.changeset/chilly-worms-speak.md

helpers/env-variables.ts

helpers/providers/index.ts

helpers/providers/mistral.ts

helpers/python.ts

helpers/types.ts

templates/components/settings/python/settings.py

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

...es/types/streaming/nextjs/app/api/chat/engine/settings.ts