fix: Robust GitHub Actions build

- Add explicit 'package' script to package.json to avoid npx issues
- Update workflow to use 'npm run package'
- Use wildcard path for compression to handle folder naming variations
- Add 'ls dist' for debugging

package.json

@@ -8,6 +8,7 @@
     "electron": "electron .",
     "build": "electron-builder build --win --publish never",
     "build:dir": "electron-builder build --win --dir",
+    "package": "electron-packager . \"Advanced-SMTP-Tester\" --platform=win32 --arch=x64 --out=dist --overwrite",
     "test": "echo \"Error: no test specified\" && exit 1"
   },
   "repository": {
@@ -81,4 +82,4 @@
       "artifactName": "${productName}-${version}-portable.${ext}"
     }
   }
-}
+}