collaborative editing: bake web version into room name #3101

Initial Checklist

• I understand this is a user story and questions should be posted in the Community Discussions
• I searched issues and couldn’t find anything (or linked relevant results below)

User Story

As a user, I want peers running a different app version to never share a collaboration session with me so that incompatible document schemas cannot corrupt the file I am editing.

Context

This can happen e.g. if OpenCloud gets updated and an active user doesn't do a page reload, or if we decide to introduce A/B testing at some point in the very far future.

User Value

Data integrity, upgrade safety

Acceptance Criteria

• The room name contains the web version (e.g. <fileId>:<webVersion>; webVersion being the actual version from the main web package.json)
• The existing version gates are removed removed (appVersion in _oc_meta)
• Unit test for the room name generation covering equal and differing versions

-> Result: Two clients on different app versions join different rooms and therefore never exchange updates. Eventually, one client will save first, the other will get a conflict.