chore: [SDK-5068] raise minimum iOS version to 12

[fadi-george]

Description

One Line Summary

Raise the OneSignal iOS SDK minimum supported deployment target from iOS 11 to iOS 12.

Details

Motivation

Align the SDK's package metadata, Xcode targets, and support tooling with the documented iOS 12 minimum.

Scope

Updates Swift Package Manager, CocoaPods, SDK and development-app Xcode deployment targets, and the GitHub bug report template. No runtime behavior or public APIs change.

Other

Multi-model review completed with no blocking findings.

Testing

Unit testing

No unit tests were added because this change only updates deployment and package configuration.

Manual testing

• swift package dump-package
• Ruby syntax validation for both podspecs
• plutil and xcodebuild -list validation for both Xcode projects
• Release build of the OneSignalCore scheme for a generic iOS Simulator destination

The targeted build passed with existing compiler deprecation and null-conversion warnings. Full CI will run on this PR. Device testing is not applicable to a configuration-only change.

Affected code checklist

• Notifications
  • Display
  • Open
  • Push Processing
  • Confirm Deliveries
• Outcomes
• Sessions
• In-App Messaging
• REST API requests
• Public API changes

Checklist

Overview

• I have filled out all REQUIRED sections above
• PR does one thing
  • If it is hard to explain how any codes changes are related to each other then it most likely needs to be more than one PR
• Any Public API changes are explained in the PR details and conform to existing APIs

Testing

• I have included test coverage for these changes, or explained why they are not needed
• All automated tests pass, or I explained why that is not possible
• I have personally tested this on my device, or explained why that is not possible

Final pass

• Code is as readable as possible.
  • Simplify with less code, followed by splitting up code into well named functions and variables, followed by adding comments to the code.
• I have reviewed this PR myself, ensuring it meets each checklist item
  • WIP (Work In Progress) is ok, but explain what is still in progress and what you would like feedback on. Start the PR title with "WIP" to indicate this.

Made with Cursor

[nan-li]

LGTM, we also have dead code in the SDK, can be a backlogged ticket to clean those up too

[fadi-george]

Tracked the dead-code cleanup in SDK-5084.