Schema generation fails for recursive type aliases

[eb8680]

The following code

import pydantic
from effectful.handlers.llm.harness.serialization import _inline_refs

type A[T] = T | list[A[T]]
_inline_refs(pydantic.TypeAdapter(A).json_schema())

fails with a RecursionError:

...
  File "/Users/eli/development/effectful/effectful/handlers/llm/harness/serialization.py", line 305, in _resolve
    return [_resolve(item) for item in obj]
            ~~~~~~~~^^^^^^
RecursionError: maximum recursion depth exceeded

This is a bug in the _inline_refs helper.