Generic and Publicly available Healthcheck API endpoint

Before You Submit

• I have checked for existing issues and pull requests related to my suggestion.
• I have posted on the Nextcloud Community Help Forum if my suggestion is a troubleshooting scenario or I'm unsure about the solution.

Type of Suggestion

Suggesting an improvement

Relevant Documentation Links

https://docs.nextcloud.com/server/stable/developer_manual/client_apis/general.html

Summary

Generic and Publicly Available Healthcheck API Endpoint With or Without Basic Auth via Headers

Details

Grabbing server startup health for Nextcloud Server seems way too complicated just for an external uptime server to display a server status.
The documentation never talks about an endpoint that can be GET'ed at to view a JSON formatted text to process if a server is online or not.

This should be easily accessible with or without a header basic authentication / bearer token.

Additional Notes

So far, all REST API endpoints stated on the documentation result to a CSRF token error, with no possible way to input a header basic authentication / bearer token. At least not stated in the Parameters section.

Looking at developer tools' network tab shows a heartbeat?format=json but uses a PUT method which tells me this is not what I need. The URL also shows apps/user_status which just solidifies my theory this is for letting the server know that a user is actively viewing the frontend so it shouldn't timeout the user.

Start with the linked developer manual page at developer_manual/client_apis/general.html and review how the existing REST endpoints describe authentication and responses. Clarify whether the request is for a new public healthcheck endpoint or documentation of an existing one; done should include an explicit endpoint, response format, and authentication behavior.