Fetches the full models.dev catalog and writes it to priv/models/models_dev.json.

mix omni.snapshot

The snapshot content is the raw API response — all providers, no transformation, no filtering. Omni.Sources.ModelsDev transforms it into %Omni.Model{} structs at load time; keeping the snapshot unpruned lets custom providers point at any models.dev catalog, not just Omni's built-ins.

Only the encoding is normalized: pretty-printed with keys sorted at every level, so successive snapshots produce minimal, reviewable git diffs.

This is a maintainer task: the snapshot is checked into the repo and shipped in the package. Run it manually when model data needs refreshing, and update the golden test expectations alongside the new snapshot.