feat(api): Add gpt-5.5 and tool name/namespace to Responses types (#3569)

## Summary

Allow the new gpt-5.5 model in Responses-related parameters and events,
and expose optional name and namespace metadata on function/tool call
output items in both beta and stable types. These are additive,
backward-compatible SDK changes.

## Changes

- Allow the model value "gpt-5.5" in all Responses-related model/type
unions and parameter definitions (chat model literals used by Responses
create/compact params and client event types) for both beta and stable
APIs.
- Add optional name: Optional[str] and namespace: Optional[str] fields
to function/tool-call output item models in both beta and stable (model
classes) so callers can access the producing tool's name and namespace.
- Add corresponding optional name and namespace entries to the TypedDict
parameter representations for function/tool-call output items (beta and
stable) so typed request/response shapes include the new metadata.
- No public symbols were removed or renamed and all additions are
optional; there are no breaking API contract changes.

Internal pull request:
https://github.com/openai/openai-python-internal/pull/15

## Validation

- Generated SDK changes were copied from the internal pull request.
- Public SDK CI runs against this draft pull request.

Co-authored-by: apcha-oai <228803254+apcha-oai@users.noreply.github.com>