fix(types): make ShowResponse.model_info optional so cloud models without model_info parse (#607)

[Missing-Identity]

Summary

Fixes #607.

ShowResponse.modelinfo is annotated Optional[Mapping[str, Any]] but declared with Field(alias='model_info') and no default. In pydantic, a field with an alias and no default is still required at validation time, so any /api/show response that omits model_info raises:

pydantic_core._pydantic_core.ValidationError: 1 validation error for ShowResponse
model_info
  Field required [type=missing, ...]

This is observed with several cloud models whose /api/show payload does not include model_info (e.g. glm-4.7:cloud, qwen3-next:80b-cloud, deepseek-v3.2:cloud), and it breaks ollama.show() as well as downstream tools such as llm-ollama.

Every other field on ShowResponse (modified_at, template, modelfile, license, details, parameters, capabilities) already has a default and is therefore optional. modelinfo is the only field that is accidentally required.

Change

- modelinfo: Optional[Mapping[str, Any]] = Field(alias='model_info')
+ modelinfo: Optional[Mapping[str, Any]] = Field(None, alias='model_info')

Giving the Field a default of None makes the field truly optional, matching its Optional[...] annotation and the rest of the model. The wire alias model_info is unchanged, so responses that include model_info continue to populate .modelinfo exactly as before.

Tests

Added two focused regression tests to tests/test_type_serialization.py:

• test_show_response_missing_model_info — a payload without model_info now validates and .modelinfo is None (other fields like capabilities/template still parse).
• test_show_response_with_model_info — a payload with model_info still populates .modelinfo correctly.

Full suite for the touched file:

12 passed in 0.15s

ruff reports All checks passed!.

Notes

This is a minimal, backwards-compatible change. No public API or wire format changes.