fix(openapi): handle circular references when writing request body schemas

[boyney123]

What This PR Does

The OpenAPI generator previously only guarded response-schema serialization against circular references. Request bodies that contained circular $refs (for example self-referencing oneOf / allOf constructs) would cause JSON.stringify to throw, aborting the schema file write for that message. This PR reuses a single circular-safe stringifier for both request bodies and responses so recursive schemas still produce a request-body.json / response-*.json with cycles marked as "[Circular]".

Changes Overview

Key Changes

• Extract a stringifySchema helper that walks the schema with a WeakSet and replaces seen objects with "[Circular]".
• Use the helper for both request-body.json and response-*.json writes in processMessagesForOpenAPISpec.
• Add a regression test plus a circular-request-body.json fixture exercising deeply nested oneOf / allOf cycles.
• Minor: ignore .pnpm-store and fix trailing newline in root .gitignore.

How It Works

stringifySchema is a thin wrapper around JSON.stringify with a replacer that tracks visited objects in a WeakSet. When the same object reference is encountered a second time during serialization, it is emitted as the string "[Circular]" instead of recursing. The existing response-side try/catch + inline replacer is removed in favor of calling this helper directly, and the request-body branch is updated to use it as well.

The new test feeds an OpenAPI spec whose request body schema has a cycle via oneOf → allOf back to an ancestor, then asserts:

• Non-circular fields still serialize with their original types.
• The cycle point in the request body is replaced with the "[Circular]" sentinel.

Breaking Changes

None. Output for non-circular schemas is byte-identical; only previously-failing circular request bodies are affected.

Additional Notes

• Changeset: @eventcatalog/generator-openapi patch.
• No public API changes; helper is module-local.

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🦋 Changeset detected

Latest commit: e941b6e

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
@eventcatalog/generator-openapi	Patch

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