Capture new metrics for AI Agent requests

[mneudert]

Description:

The new "Agent Mode" provided by ChatGPT/NovaAct is using a real browser instance to perform tasks on behalf of the user.

At the moment these visits are tracked just like any other browser, and there is no way to detect them and generate metrics/reports for those agents.

A new AIAgents plugin will flag NovaAct and ChatGPT requests, and prepares flagging other agents once we know how to detect them. The plugin uses two new dependent segments ("ai agent" and "human") to provide VisitSummary metrics.

Review

• Functional review done
• Potential edge cases thought about (behavior of the code with strange input, with strange internal state or possible interactions with other Matomo subsystems)
• Usability review done (is anything maybe unclear or think about anything that would cause people to reach out to support)
• Security review done
• Wording review done
• Code review done
• Tests were added if useful/possible
• Reviewed for breaking changes
• Developer changelog updated if needed
• Documentation added if needed
• Existing documentation updated if needed

[sgiehl]

Code overall looks clean and straight forward. No real issues found.
However, I've left a couple of questions that we should clarify before merging.

[michalkleiner]

Was just having a look through the code to see how things are done, and left a few minor comments along the way, hope that's ok :)

[sgiehl]

Seems some new related tests are failing for PHP 8, those might need some investigation. Otherwise everything looks fine

[mneudert]

Forced a specific date setup in that test. With "now = 12:00" and tracking data being created from 06:00 on. Worked at least the last CI run, but then again it did not fail for most runs before 🙈