Recursive `z.lazy()` schemas produce broken `$ref` cycles in OpenAPI output

[bravehager]

We use hono-openapi to generate an OpenAPI spec from Zod v4 schemas. One of our schemas uses z.lazy() for a recursive condition builder:

const ConditionGroup: z.ZodType<any> = z
  .object({
    operator: z.enum(["AND", "OR"]),
    conditions: z.array(z.lazy(() => z.union([Condition, ConditionGroup]))),
  })
  .meta({ ref: "ConditionGroup" });

The generated spec contains $ref: "#/components/schemas/__schema0" and $ref: "#/components/schemas/#" instead of resolving to ConditionGroup. This breaks openapi-typescript codegen and any client that tries to dereference the spec.

I have a fix on my fork: https://github.com/bravehager/standard-openapi/tree/fix/recursive-schema-refs.

I'm opening an issue before a PR because the fix is fairly involved. I needed some help from Claude to even debug what was going on in the conversion pipeline, let alone come up with a working solution. Would love a sanity check before submitting a PR.