docs: add ios testflight handoff

Author: jjoonleo

handoff/ios-testflight-1.0.0.md

@@ -0,0 +1,39 @@
+# iOS TestFlight 1.0.0 Handoff
+
+## Status
+
+- `release/1.0.0` was fast-forwarded to the current `main` candidate.
+- Android closed testing already has `1.0.0 (53)` from workflow run `28080538591` on `hotfix/remove-full-screen-intent`.
+- The iOS bundle identifier is confirmed as `club.devkor.ontime.ios`.
+- `docs/Release-Checklist.md` was corrected to use `club.devkor.ontime.ios`.
+- `flutter pub get`, `dart run build_runner build --delete-conflicting-outputs`, `flutter analyze`, and `flutter test` passed locally.
+- iOS archive succeeded at `build/ios/archive/Runner.xcarchive`.
+
+## Blocker
+
+`flutter build ipa` could not export an App Store IPA because local Xcode has no Apple account configured and no `iOS Distribution` signing certificate or provisioning profile for `club.devkor.ontime.ios`.
+
+Observed export errors:
+
+```text
+error: exportArchive No Accounts
+error: exportArchive No signing certificate "iOS Distribution" found
+error: exportArchive No profiles for 'club.devkor.ontime.ios' were found
+```
+
+## Next Steps
+
+1. Sign in to Xcode with an Apple Developer account that belongs to team `FV4XWCGPRZ`.
+2. Ensure the App Store Connect app and bundle identifier `club.devkor.ontime.ios` exist.
+3. Let Xcode automatic signing create or download an App Store provisioning profile, or install the team's distribution certificate/profile manually.
+4. Re-run:
+
+```sh
+flutter build ipa --release \
+  --dart-define=ENV=staging \
+  --dart-define=GOOGLE_RESERVED_CLIENT_ID_IOS=$(plutil -extract REVERSED_CLIENT_ID raw ios/GoogleService-Info.plist) \
+  --dart-define=REST_API_URL=https://ontime-back.duckdns.org
+```
+
+5. Upload the exported IPA to TestFlight through Xcode Organizer or Transporter.
+6. If iOS TestFlight becomes the shared QA candidate, upload Android closed testing again from the same `release/1.0.0` branch with Android `versionCode` `54` or higher.