ci: use Xcode 26.6

[robertherber]

Summary

• move the iOS CI job to the macos-26 runner
• select stable Xcode 26.6 explicitly
• run the build and HealthKit contracts on an iPhone 17 Pro with iOS 26.5

Context

Xcode 26.6 is Apple’s latest stable release, but it is only installed on GitHub’s macOS 26 runner image. The macOS 15 runner only provides Xcode through 26.3.

Validation

• bun typecheck
• bun lint
• parsed .github/workflows/test.yml with Ruby YAML
• git diff --check
• pre-push tests: 9 passed, 0 failed

🤖 Generated with Claude Code

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Latest commit: e25d8d8

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[Copilot]

Pull request overview

Updates the iOS CI workflow to run against the newer GitHub-hosted macOS 26 environment and targets newer Apple toolchain/runtime versions to validate the example iOS build and HealthKit contract checks.

Changes:

• Switch the iOS CI job runner from macos-15 to macos-26.
• Pin Xcode selection to a specific bundle path (/Applications/Xcode_26.6.app).
• Tighten simulator selection to an iPhone 17 Pro on iOS 26.5 and simplify applesimutils installation.

[pkg-pr-new]

Open in StackBlitz

npm i https://pkg.pr.new/kingstinct/react-native-healthkit/@kingstinct/react-native-healthkit@364

commit: e25d8d8