feat(analytics-react-native): add appLifecycles plugin

[daniel-graham-amplitude]

Summary

Checklist

• Does your PR title have the correct title format?
• Does your PR have a breaking change?:

---

Note

Low Risk
Optional analytics enrichment with no auth or data-model changes; behavior is covered by unit tests including subscription teardown.

Overview
Adds appLifecyclePlugin to @amplitude/analytics-react-native, exported from the package entry point. The enrichment plugin listens to React Native AppState and emits [Amplitude] Application Opened when the app becomes active and [Amplitude] Application Backgrounded when it goes to background; it logs if AppState is missing and cleans up via remove() or legacy removeEventListener.

The Expo example wires add(appLifecyclePlugin()) instead of the browser page-view plugin and drops the previous autocapture init options. Unit tests cover setup, tracking, pass-through execute, teardown, and the unavailable-AppState path.

^{Reviewed by Cursor Bugbot for commit a8054d9. Bugbot is set up for automated code reviews on this repo. Configure here.}

[linear-code]

SDK-45

[github-actions]

size-limit report 📦

Path	Size
packages/analytics-browser/lib/scripts/amplitude-min.js.gz	58.31 KB (0%)
packages/session-replay-browser/lib/scripts/session-replay-browser-min.js.gz	131.96 KB (0%)
packages/unified/lib/scripts/amplitude-min.umd.js.gz	208.94 KB (0%)