Automate iOS distribution with Fastlane for TestFlight beta delivery and App Store releases. Use when setting up `fastlane/` in an Xcode project, creating or editing lanes (e.g. `beta`, `release`, `appstore`), configuring App Store Connect API keys / signing, uploading builds via `pilot` / `upload_to_testflight`, submitting releases via `deliver` / `upload_to_app_store`, or debugging common Fastlane build/signing/upload failures in CI.