Support for iOS 26 “Declared Age Range” Framework

Apple introduced the new [`DeclaredAgeRange`](https://developer.apple.com/documentation/declaredagerange) framework in iOS 26, which allows apps to request a user’s declared age range (e.g., “13–15”, “16 or older”) in a privacy-preserving way.

It would be extremely helpful if .NET for iOS/macOS included official bindings for this framework. Is this planned for future releases?

### Why this is important
- **Regulatory compliance:** Laws such as Texas’s Texas Senate Bill 2420 require age-appropriate experiences and age verification in apps starting January 1, 2026! The Declared Age Range framework enables meeting such legal requirements while protecting user privacy.
- **Privacy first:** Apple's commentary emphasizes that the mechanism avoids collection of full birthdates, enabling “age-appropriate experiences … without the App Store collecting unnecessary sensitive personal data.”

### References
- Apple documentation: https://developer.apple.com/documentation/declaredagerange
- Apple Newsroom: https://www.apple.com/newsroom/2025/06/apple-expands-tools-to-help-parents-protect-kids-and-teens-online/
- Legislative context (TX SB 2420): https://capitol.texas.gov/BillLookup/History.aspx?LegSess=88R&Bill=SB2420

### Suggested labels
`enhancement`, `iOS26`, `feature-request`, `age range`, `child-safety`