Adds fastlane Appfile/Fastfile (upload_only lane that pushes an already-
exported IPA to TestFlight via the ASC API key) and the generated README.
The ASC .p8 private key stays outside the repo (~/.appstoreconnect); only
its key_id/issuer_id identifiers are referenced. Gitignores the transient
fastlane/report.xml run artifact.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Trey T