feat: detect Swift Package Manager projects

[thymikee]

Summary

Fixes #2856

React Native 0.87 ships react-native spm, which migrates the Xcode project to Swift Package Manager, strips React Native out of the Podfile and leaves the file on disk. We treated those projects as broken: with no Podfile found, getProjectConfig bailed out, so config had no project.ios.sourceDir and run-ios/build-ios insisted on installing pods.

• findSpmProjectDir looks for the .xcodeproj containing .spm-injected.json — the marker react-native spm writes inside the project bundle, and react-native spm deinit removes. It wins over a leftover Podfile, since react-native spm refuses to migrate a CocoaPods-integrated project anyway.
• project.ios.buildSystem is spm or cocoapods, so commands know where React Native comes from.
• resolvePods returns whether pods were installed, instead of both callers setting installedPods = true next to it, and skips CocoaPods for spm projects. --force-pods / --only-pods still run it, which is how pods unrelated to React Native keep working next to Swift Package Manager. Forcing pods where there is no Podfile now errors with a hint to run react-native spm.

Libraries still need a Package.swift, which is RN's react-native spm scaffold + patch-package story. Nothing to configure in the CLI anymore — no project.ios.sourceDir, no automaticPodsInstallation: false, no stub Podfile, e.g. the ones needed in bottom-tabs' SPM example.

Test Plan

yarn test packages/cli-config-apple

Verified against a real 0.87.1 app migrated with node node_modules/react-native/scripts/setup-apple-spm.js add --deintegrate --yes, with this build linked into node_modules:

$ npx react-native config | jq '.project.ios | {sourceDir, buildSystem}'
{
  "sourceDir": "/tmp/spm-proto/SpmApp/ios",
  "buildSystem": "spm"
}

$ npx react-native build-ios
success Successfully built the app

$ npx react-native run-ios --simulator "Apex CI Smoke" --port 8090
success Successfully built the app
success Successfully launched the app

Debug and Release both build, install, launch and render the app; no CocoaPods step runs. RN's own generate-spm-autolinking-config.js succeeds against this config output — before the change it failed with CLI config did not provide project.ios.sourceDir. A CocoaPods project's output is identical apart from buildSystem: "cocoapods", so the e2e snapshot is updated for that.

One unrelated thing I tripped over: run-ios --port starts the dev server on that port, but installApp launches the app with a bare simctl launch, so the app still asks the packager on 8081. I had to launch with -RCT_jsLocation localhost:8090 to load my bundle. Worth a separate issue.

Checklist

• Documentation is up to date.
• Follows commit message convention described in CONTRIBUTING.md.
• For functional changes, my test plan has linked these CLI changes into a local react-native checkout (instructions).