feat: add acknowledged React Native deep-link routing (MBL-2301)

[Shahroz16]

What changed

• Adds an opt-in CustomerIO.setDeepLinkHandler API for React Native UIScene hosts.
• Buffers cold destinations until the handler registers, then requires an explicit handled or declined result.
• Uses the native fallback for a declined URL, handler failure, missing registration, or timeout.
• Preserves the existing Linking readiness path and AppDelegate behavior.
• Routes cold and warm Live Activity destinations through the same acknowledged path.
• Keeps Android behavior unchanged.

Validation

• Package build and TypeScript declarations
• API Extractor
• ESLint
• 17 Jest tests
• Native Swift request-state and acknowledgement race tests
• Packed SDK built into a React Native 0.88 scene sample
• Maestro cold and warm notification destination tests on Xcode 26.6 and iOS 26.5
• The PR workflow provides the Xcode 27 build and launch check

Scope

This is the post-release single-scene reliability follow-up tracked by MBL-2301. Multi-window scene ownership remains separate work.

[github-actions]

Sample app builds 📱

Below you will find the list of the latest versions of the sample apps. It's recommended to always download the latest builds of the sample apps to accurately test the pull request.

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• iOS FCM: 648.6.0 (29799082)
• Android APN: 648.6.0 (29799082)

[mrehan27]

Approving. The state machine holds up under pressure: the expectedState guards mean a request promoted by useHandler() no-ops its stale readiness timer instead of double-falling-back, every promoted delivery gets its own acknowledgement timer, and fallback() is only ever reached after the lock is released at all three call sites.

This also closes both P2s from #643 — Maestro is pinned to the release URL with a checksum, and the paths filter now covers src/** and ios/wrappers/**. Worth noting test.yml had no npm test step before this, so it's also the first CI gate for the Jest suite, alongside the new Swift state tests.