add iPad detection and device class cookie setting

[juabara]

What does this change?

Implements client-side iPad detection to set a device_class cookie for proper backend targeting. Detects both older iPads (iOS 12 and earlier via navigator.platform) and newer iPads (iPadOS 13+ which report as MacIntel but have touch support). The cookie is set early in the client startup process before SDC requests are made.

[github-actions]

Hello 👋! When you're ready to run Chromatic, please apply the run_chromatic label to this PR.

You will need to reapply the label each time you want to run Chromatic.

Click here to see the Chromatic project.

[github-actions]

Deploy build 23313 of dotcom:rendering-all to CODE

All deployment options

• Deploy build 23313 of dotcom:rendering-all to CODE
• Deploy parts of build 23313 to CODE by previewing it first
• What's on CODE right now?

---

From guardian/actions-riff-raff.

[juabara]

I'm not sure if this is the best place to call this function.

[SiAdcock]

Hi @juabara.

I haven't looked at the code change too closely, but it would be useful to know why we need to detect that the user is browsing on an iPad.

Also, if we're dropping a new cookie, it would also be reassuring to know that @guardian/identity are aware and that it has been cleared from a data privacy perspective.

Could you add a bit more info to the PR? Alternatively I'll be happy to chat if it's easier. Thanks so much!

[theemilyturner]

Hi @juabara.

I haven't looked at the code change too closely, but it would be useful to know why we need to detect that the user is browsing on an iPad.

Also, if we're dropping a new cookie, it would also be reassuring to know that @guardian/identity are aware and that it has been cleared from a data privacy perspective.

Could you add a bit more info to the PR? Alternatively I'll be happy to chat if it's easier. Thanks so much!

Hi @juabara , on this, as Simon has mentioned, any new cookies need to be documented and confirmed as essential by the Data Privacy team, please fill out this form and let me know when you have done so to kick off the process. Thank you.
https://docs.google.com/forms/d/1kk9ya8OWnMzexJcrY0W4uk9WLQGUHGnbk-85osrqch0/