fix: update AtomicSDK version to 3.27.2 with vendored_frameworks

[brax10ward]

Linear Link

https://linear.app/atomic/issue/SDK-422/ios-sdk-version-mismatch-in-react-native-podspec

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Refactor (non-breaking change which cleans up code)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update
• This change impacts security

Summary

The AtomicSDK CocoaPods dependency version was only updated in one of two podspec branches, causing customers on RN >= 0.71.0 to get 3.26.0 instead of the intended 3.27.1 (SDK-422).

To prevent this class of bug entirely, this PR:

• Vendors AtomicSDK XCFrameworks directly into ios/frameworks/ instead of relying on CocoaPods dependency resolution
• Adds scripts/update-ios-sdk.sh to download and update frameworks from GitHub releases
• Adds update-ios-sdk.yml workflow that auto-creates a PR when a new iOS SDK is released (triggered via repository_dispatch from the iOS SDK repo, with auto-merge enabled)
• Tracks vendored version in ios/frameworks/.sdk-version

Follow-up needed

Add a repository_dispatch step to atomicfi/atomic-transact-ios create_release.yml to trigger the auto-update workflow in this repo.

Checklist:

• New and existing tests pass locally with my changes
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have tested on a physical iOS device and Android device
• I have added tests that prove my fix is effective or that my feature works
• I have followed the Code Review and Code Review Security guidelines
• I have checked my code against flaws from the OWASP Top 10
  • A01:2021-Broken Access Control
  • A02:2021-Cryptographic Failures
  • A03:2021-Injection
  • A04:2021-Insecure Design
  • A05:2021-Security Misconfiguration
  • A06:2021-Vulnerable and Outdated Components
  • A07:2021-Identification and Authentication Failures
  • A08:2021-Software and Data Integrity Failures
  • A09:2021-Security Logging and Monitoring Failures
  • A10:2021-Server-Side Request Forgery