v10 slice 5: example app on v10, test seam, CI, docs, version 10.0.0

[dmurphy5]

Summary

This PR prepares v10 for release. It has no new upload behavior. It adds the tools that the release needs: a test app for device runs, a way for an app to test its own upload code without a device, CI for the iOS tests, and the final docs and version number.

1. The example app is now the device test script

The example app in example/RNBGUExample uses the v10 API. Every step of the device test (send a JSON request, upload a photo, upload a large file in parts, pause, resume, cancel, refresh a token, kill the app and relaunch, turn on Wi-Fi only) has a button. A small local server answers each test case (401, 404, 409, slow, oversize) so a tester does not need a backend. The app README lists the steps for both platforms.

2. Apps can test their upload code without native code

flowchart LR
    subgraph App tests
        T[Test] --> D[Your definitions and handlers]
    end
    D --> L[Real library logic]
    L --> F[Fake native queue]
    F -- "settle(id, outcome)" --> L
    L --> D

Loading

createUploadClient({ native }) accepts a fake in place of the native module, and createFakeNative() supplies one. A test defines a request, calls mutate(), asks the fake to "settle" it with a success or error, and checks that the handler did the right thing. The real registry and delivery code run in between, so the test proves the same path that runs on a device. Diana's Jest suite will use this.

3. CI runs the iOS tests

A macOS job runs swift test. Until now only the Android unit tests ran in CI.

4. Docs and version

1. CHANGELOG 10.0.0 covers every change across the v10 PRs, with each removed function and its replacement.
2. README: an "Upgrading from v9" section, platform notes for both OSes, a "Testing your definitions" section, and a corrected iOS setup snippet.
3. Version 10.0.0 in package.json.

What to look at

1. example/RNBGUExample/README.md, "Device test script": is each step clear enough to run?
2. README, "Upgrading from v9": does it answer what happens to uploads that were in flight at upgrade time?

Test Plan

yarn typecheck && yarn test && yarn lint:ci        # 171 tests
cd ios && swift test                               # 178 tests
cd example/RNBGUExample/android && ./gradlew :react-native-background-upload:testDebugUnitTest :app:assembleDebug
cd example/RNBGUExample/ios && pod install && xcodebuild ... build

The macOS CI job runs for the first time on this PR.

Compatibility

OS	Implemented
iOS	✅
Android	✅

Checklist

• I have tested this on a device and a simulator
• I added the documentation in README.md
• I updated the typed files (TS)
• I've added Detox End-to-End Test(s)
• I've created a snack to demonstrate the changes

🤖 Generated with Claude Code