Add CI cert import + cleanup to prevent certificate limit issues

- Import stored distribution cert from DISTRIBUTION_CERTIFICATE_BASE64 secret
- Add ASC API cert cleanup script (revokes excess dev/dist certs)
- Consistent cert management pattern across all iOS repos

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: wdvr

.github/workflows/ios-build.yml

@@ -40,5 +40,4 @@ jobs:
       APP_STORE_CONNECT_PRIVATE_KEY: ${{ secrets.APP_STORE_CONNECT_PRIVATE_KEY }}
       DISTRIBUTION_CERTIFICATE_BASE64: ${{ secrets.DISTRIBUTION_CERTIFICATE_BASE64 }}
       DISTRIBUTION_CERTIFICATE_PASSWORD: ${{ secrets.DISTRIBUTION_CERTIFICATE_PASSWORD }}
-      KEYCHAIN_PASSWORD: ${{ secrets.KEYCHAIN_PASSWORD }}
       APPLE_TEAM_ID: ${{ secrets.APPLE_TEAM_ID }}