[alieldab3]

fix(ios): Guard newer APIs for older SDK compatibility

Summary

• Add compile-time guards around iOS 27.0 and 27.1 APIs while preserving runtime availability checks.
• Retain older-SDK fallbacks and accurately report unsupported Duo capabilities.
• Preserve Duo functionality on supported SDK/runtime combinations.
• Normalize added preprocessor directives to column 1.

Validation

• Consuming-app simulator builds succeeded with Xcode 26.3 and 27.1.
• The 26.3-built app launched on a standard iPhone simulator.
• git diff --check passed.
• All 19 focused native policy tests passed.
• SDK guard preprocessing checks passed for 26.3, 27.0, and 27.1.
• Full tooling suite: 58/59 passed; one failed because the example's Expo dependency was missing.

Limitations

• Preprocessing checks do not replace full native builds.
• Duo folding and physical hardware behavior remain untested.
• SDKs predating iOS 26 are not covered by this compatibility claim.

[CAWRESTLER]

Thanks for this, @alieldab3! The guard approach looks right and CI is green on Xcode 27.1. Two small things before I merge:

1. Unused static helpers on older SDKs. In ios/RNDuoArrangementView.mm, RNDuoAxes and RNDuoOverlayEdge are only called from code that's now inside the iOS 27 compile-time guard, so on older Xcode they're unused and trigger -Wunused-function. That will break builds for apps compiling with -Werror. Could you wrap those two helpers in the same #if guard?
2. Branch is behind main. Please update/rebase onto the latest main so the required checks can run against it.

Optional, fine as a follow-up: the README, docs/COMPATIBILITY.md, and CHANGELOG still say Xcode 27.1 is required to compile. With this PR, older Xcode builds succeed and report Duo features as unavailable, so a note there would help. I can handle that after merge if you'd rather not.

Thanks again for the contribution!

[alieldab3]

Thanks @CAWRESTLER for the review! Both helpers are now wrapped in the same SDK guard, and I’ve updated the README, compatibility guide, and changelog to clarify older-SDK fallback behavior.

I also fetched the latest upstream main and confirmed it’s already included in this branch through the existing merge. All 19 focused native tests and git diff --check pass.

I’ll commit and push these local updates so CI can rerun.

[CAWRESTLER]

Thanks @alieldab3! Both helpers are guarded, the docs are updated, and CI is green on all platforms. Merging.