Make activity number unique within a project instead of the whole Kimai installation

[MartinRyx]

Describe the problem

For now, the newly added activity number has to be unique throughout "my" Kimai installation. In my case, the activity number is "owned" by my customers and I can't change them (they belong to the customers issue tracker) and if two customers come up with the same activity number, Kimai is unable to handle that.

Describe the solution you'd like

I think it would work better if the activity number is unique within either a customer, but even better within a project.

Describe alternatives you've considered

Until now I've used a custom field for activity number, but it would be better to be able to use the activity number field instead

Screenshots

No response