Fix(toolService): Create union type for multiple response schemas

The toolService.mjs was not correctly interpreting the OpenAPI specification to create a comprehensive output schema for tools. It only considered success responses (200, 201, 202), ignoring defined error responses (e.g., 500, 404).

This caused the MCP client to reject valid error objects returned by tools, as they did not match the success-only output schema.

This ticket covers the fix implemented in buildOutputZodSchema to iterate over all possible responses for an operation and combine their schemas into a z.union() type. This ensures the generated outputSchema accurately reflects all possible return shapes (both success and error), making the tool definitions more robust.