ci: fix signing style inconsistency to prevent permission resets on update

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

Author: mxvsh

.github/workflows/build.yml

@@ -93,7 +93,7 @@ jobs:
             <key>method</key>
             <string>developer-id</string>
             <key>signingStyle</key>
-            <string>automatic</string>
+            <string>manual</string>
             <key>signingCertificate</key>
             <string>Developer ID Application</string>
             <key>teamID</key>