feat: Add e2b code artifact tool support for the FastAPI template (#339)

.changeset/shiny-lamps-retire.md

e2e/python/resolve_dependencies.spec.ts

helpers/python.ts

helpers/tools.ts

templates/components/engines/python/agent/tools/artifact.py

templates/components/routers/python/sandbox.py

...lates/types/streaming/fastapi/app/api/routers/__init__.py

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

...s/types/streaming/fastapi/app/engine/utils/file_helper.py

templates/types/streaming/fastapi/main.py

...eaming/nextjs/app/components/ui/chat/widgets/Artifact.tsx