TestFlight is now opt-in (default OFF). A workflow_dispatch boolean
`enable_testflight` (or the `ENABLE_TESTFLIGHT` repo variable) drives a
`prepare.outputs.testflight_enabled` flag that gates the macOS
app-store-pkg build leg and both testflight_ios/testflight_macos upload
legs. Missing Apple signing secrets no longer fail the normal DMG/IPA
release path (package-macos-app-store-pkg.sh hard-exits without them).
Xcode 27 build compatibility:
- Align Apple deployment targets so no pod sits below the app minimum
(Xcode 27 rejects this): macOS pods + RunnerTests -> 15.6, iOS pods
-> 15.5 to match the Runner targets.
- Add a `lipo` shim (scripts/xcode-tools/lipo) wired onto PATH in the
iOS/macOS build phases; Xcode 27 only accepts one `-verify_arch`
architecture per call while Flutter passes them all at once.
- macOS project hygiene: correct PrivacyInfo.xcprivacy path, set app
display name + LSApplicationCategoryType.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
