Add openContactsPicker to edit the limited contacts selection on iOS 18+

[pablogdcr]

Summary

iOS 18 added limited contacts access. This adds openContactsPicker() to let the user update their selection when the Contacts permission is limited, same as openPhotoPicker() does for the photo library (related: #894, #895).

Apple only exposes this picker as a SwiftUI modifier (contactAccessPicker), so the Contacts handler gets a small Swift file presenting it through a UIHostingController. The ObjC handler calls it via NSClassFromString + a protocol, which works the same with static libs and use_frameworks! without touching the module setup. setup.rb now globs *.swift and links ContactsUI, and the podspec declares swift_version.

Test Plan

Tested in the example app on an iPhone 16 Pro simulator (iOS 18.6), with both the default pod install and USE_FRAMEWORKS=dynamic.

What's required for testing (prerequisites)?

An iOS 18+ simulator. Contacts is already enabled in the example Podfile.

What are the steps to test it (after prerequisites)?

• Request CONTACTS and pick "Select Contacts" → status is limited
• Tap the new toolbar button → the contact access picker opens, edit the selection, tap Done → the promise resolves
• With full access, denied or not determined → rejects with "Contacts permission isn't limited"
• On iOS < 18 → rejects with "Only available on iOS 18 or higher"
• On Android → throws the JS "Only supported by iOS 18 and above" error

Compatibility

OS	Implemented
iOS	✅
Android	❌

Checklist

• I have tested this on a device and a simulator (simulator only)
• I added the documentation in README.md
• I added a sample use of the API in the example project (example/App.tsx)