fix(ios): install ubiquity observer only after emitter callback is bound

[mariusvanwyk]

Summary

Fixes #59.

RCTCloudStorageCloudKit registered its NSUbiquityIdentityDidChangeNotification observer in -init, but the observer's block ends up calling the codegen-generated -emitOnCloudAvailabilityChanged:, which invokes a std::function event-emitter callback that is only bound later via -setEventEmitterCallback:.

If iOS posts the ubiquity-change notification in the window between -init and -setEventEmitterCallback: (e.g. on app launch after a reboot, when the user signs in/out of iCloud, or when iCloud Drive is toggled), the block invokes an empty std::function, throwing std::bad_function_call and terminating the process with SIGABRT.

Fix

Move the observer installation into -setEventEmitterCallback: so it is only installed once the emitter callback is bound. -dealloc already removes the observer via the stored token, so no change needed there. The existing "emit current availability immediately after binding" behavior is preserved (we still call emitCloudAvailabilityChanged at the end of -setEventEmitterCallback:).

This matches the implementation approach proposed by @ayousufi in #59.

Crash confirmation

Two independent reports against react-native-cloud-storage@3.0.0 on iOS (New Architecture / Turbo Modules):

Exception Type: EXC_CRASH (SIGABRT)

 9 App  std::__1::__throw_bad_function_call[abi:ne200100]() + 52
10 App  std::__1::__function::__value_func<void (...)>::operator()(...) + 4
11 App  std::__1::function<void (...)>::operator()(...) + 92
12 App  -[NativeCloudStorageCloudKitIOSSpecBase emitOnCloudAvailabilityChanged:] + 64
13 App  -[RCTCloudStorageCloudKit emitCloudAvailabilityChanged] + 188
14 App  __31-[RCTCloudStorageCloudKit init]_block_invoke + 28
15 CoreFoundation  __CFNOTIFICATIONCENTER_IS_CALLING_OUT_TO_AN_OBSERVER__
...
19 Foundation      -[NSNotificationCenter postNotificationName:object:userInfo:]
20 Foundation      ___postUbqiuityAccountChangeNotification_block_invoke

Reproduced on:

• iPhone 14 Pro / iOS 26.2 (iOS: SIGABRT (bad_function_call) when NSUbiquityIdentityDidChangeNotification fires before setEventEmitterCallback binds the emitter #59)
• iPhone 17,2 / iOS 26.3.1 (crash log from TestFlight feedback)

Testing

• Before: on a device that had iCloud state change recently, the app reliably crashes within seconds of launch. Also reproducible by toggling iCloud Drive off/on in Settings while the app is foregrounded.
• After: no crash in the same scenarios. The first emit after JS binds its listener still delivers the current availability correctly (because setEventEmitterCallback: continues to call emitCloudAvailabilityChanged at the end).

Notes

• Android is unaffected — its module does not use an equivalent NSNotificationCenter-style observer.
• No API or JS-side change.

[netlify]

✅ Deploy Preview for react-native-cloud-storage ready!

Name	Link
🔨 Latest commit	9611f7a
🔍 Latest deploy log	https://app.netlify.com/projects/react-native-cloud-storage/deploys/69e48b7381d0b5000807bd99
😎 Deploy Preview	https://deploy-preview-61--react-native-cloud-storage.netlify.app
📱 Preview on mobile	Toggle QR Code... Use your smartphone camera to open QR code link.

---

To edit notification comments on pull requests, go to your Netlify project configuration.

[dzeveckij]

merge please 🙏