fix(bindings): UIScene lifecycle for RN example apps on iOS 26+

[Ankush523]

Summary

Adopts UIScene lifecycle (required on iOS 26+) for all four React Native example apps:

• examples/demo-app
• examples/react-native-app
• examples/nostr-example
• examples/mesh-wiki

What changed

• Scene lifecycle — React Native starts in SceneDelegate; AppDelegate configures the factory and scene. AppDelegate.window is set for RCTDeviceInfo and related RN APIs.
• Launch options — Shared examples/shared/ios/ReactNativeSceneLaunchOptions.swift merges application(_:didFinishLaunchingWithOptions:) with scene connectionOptions (URL, notification, user activity) before startReactNative.
• Debug JS loading — Simulator uses Metro; physical device prefers embedded main.jsbundle when present (demo README documents rebuild-after-JS for device Debug).
• Pods / toolchain — IPHONEOS_DEPLOYMENT_TARGET 15.1 in each example Podfile post_install; shared examples/shared/ios/pod_fmt_consteval_patch.rb for fmt / Xcode 26+ build failures.
• Ruby — nkf in example Gemfiles where needed for Ruby 3.4+ pod install.
• Docs (demo-app) — iOS simulator vs device Debug behavior; optional DevelopmentTeam.xcconfig.example (not wired into the Xcode target; signing still via Signing & Capabilities or your own xcconfig wiring).

Verification

Manual iOS ↔ Android BLE smoke test on Offline Demo (iPhone 12, iOS 27.0.1): onboarding, People discovery, Chats messaging.

Test plan

• Offline Demo on physical iPhone (iOS 27): launch, onboarding, People, Chats
• Offline Demo on iOS Simulator (iOS 27): xcodebuild succeeds
• Optional: pod install + iOS build for react-native-app, nostr-example, mesh-wiki on Xcode 26+

[github-actions]

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[Ankush523]

I have read the CLA Document and I hereby sign the CLA