link to and create client compliance tests

Link to problem area
No instance of compliance (testing not license) or integration (testing not manager) in the docs except:

• https://github.com/matrix-org/matrix-doc/blob/a78a8bb27d482c07ba2f0de32297345901fa1f18/proposals/1779-open-governance.md#L414
• https://github.com/matrix-org/matrix-doc/blob/a78a8bb27d482c07ba2f0de32297345901fa1f18/proposals/2540-stricter-event-validation.md#L1

Searches:
https://github.com/matrix-org/matrix-doc/search?q=integration+-%22integration+manager%22&type=
https://github.com/matrix-org/matrix-doc/search?q=compliance+-%22compliance+with+the+License.%22

Issue
Create client compliance tests. Link to suggested ones. I couldn't find any integration or compliance tests for matrix clients.

There are two projects for testing servers ( https://github.com/matrix-org/complement and https://github.com/matrix-org/sytest ), these should probably also be mentioned in the spec.

Start by reviewing proposals/1779-open-governance.md and proposals/2540-stricter-event-validation.md, then examine the referenced Complement and SyTest projects. Define the scope and location of client compliance tests and the documentation links; done means the tests exist and the relevant Matrix specification documentation points to them and the server-testing projects.