main

feat: iOS App Store signing pipeline (API-key-driven)

Following the proven appstore.md playbook (CrispChess/CrispSudoku/
CrispDeck pattern):

- ExportOptions.plist: method app-store → app-store-connect
- pbxproj: delete 3x stale CODE_SIGN_IDENTITY[sdk=iphoneos*]
  overrides that conflict with Automatic signing (Step 4 gotcha)
- .gitignore: add .appstoreconnect/ and *.p8
- release.yml: conditional signed path when APPSTORE_API_KEY_P8
  secret is set — archive → export → validate → upload to App
  Store Connect. Falls back to unsigned IPA when secret absent.

To activate: set these repo secrets in GitHub:
  APPSTORE_API_KEY_P8  (base64 of AuthKey_9RMU3C7422.p8)
  APPSTORE_APP_ID      (numeric, from App Store Connect)

Human steps still required:
  1. Create app record in App Store Connect (browser)
  2. App Privacy nutrition label (browser)
  3. Set APPSTORE_APP_ID secret after step 1

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>