- Add api.fireworks.ai to _URL_TO_PROVIDER for automatic provider detection
- Add fireworks to PROVIDER_TO_MODELS_DEV mapped to 'fireworks-ai' (the
correct models.dev provider key — original PR used 'fireworks' which
would silently fail the lookup)
Cherry-picked from PR #3989 with models.dev key fix.
Co-authored-by: sroecker <sroecker@users.noreply.github.com>