feat(spaces): registry entries for renamed BF16 aliases + seed inputs + bootstrap

fix(backend,models): runtime corrections from end-to-end testing

ci: run unit tests + ruff lint on every push

feat(models): ensure_models with HF cache symlinks + missing-file fallback

feat(models): walk_workflow_for_models scans loader nodes

feat(models): MODEL_REGISTRY mapping filenames to HF repos