Use hdiutil for DMG creation instead of create-dmg

create-dmg (brew) uses AppleScript/Finder for icon positioning which
times out on headless CI. Switch to hdiutil with Applications symlink
for reliable CI builds.

.github/workflows/release.yml

@@ -45,7 +45,6 @@ jobs:
           brew update
           brew install zig
           npm uninstall --global create-dmg 2>/dev/null || true
-          brew install create-dmg
 
       - name: Build GhosttyKit.xcframework
         run: |
@@ -161,23 +160,14 @@ jobs:
           xcrun stapler validate "$APP_PATH"
           spctl -a -vv --type execute "$APP_PATH"
           rm -f "$ZIP_SUBMIT"
-          # create-dmg (brew) generates a styled drag-to-install DMG
-          # It expects: create-dmg [options] <output.dmg> <source_folder>
-          # --no-internet-enable avoids deprecated flag warning
-          DMG_SOURCE="$(mktemp -d)"
+          # Build DMG with Applications symlink (no Finder/AppleScript needed)
+          DMG_SOURCE="$(mktemp -d)/cmuxterm"
+          mkdir -p "$DMG_SOURCE"
           cp -R "$APP_PATH" "$DMG_SOURCE/"
-          create-dmg \
-            --volname "cmuxterm" \
-            --window-pos 200 120 \
-            --window-size 660 400 \
-            --icon-size 160 \
-            --icon "cmuxterm.app" 180 170 \
-            --app-drop-link 480 170 \
-            --no-internet-enable \
-            --codesign "$APPLE_SIGNING_IDENTITY" \
-            "$DMG_RELEASE" \
-            "$DMG_SOURCE"
-          rm -rf "$DMG_SOURCE"
+          ln -s /Applications "$DMG_SOURCE/Applications"
+          hdiutil create -volname "cmuxterm" -srcfolder "$DMG_SOURCE" -ov -format UDZO "$DMG_RELEASE"
+          rm -rf "$(dirname "$DMG_SOURCE")"
+          /usr/bin/codesign --force --sign "$APPLE_SIGNING_IDENTITY" "$DMG_RELEASE"
           DMG_SUBMIT_JSON="$(xcrun notarytool submit "$DMG_RELEASE" --apple-id "$APPLE_ID" --team-id "$APPLE_TEAM_ID" --password "$APPLE_APP_SPECIFIC_PASSWORD" --wait --output-format json)"
           DMG_SUBMIT_ID="$(python3 -c 'import json,sys; print(json.load(sys.stdin)["id"])' <<<"$DMG_SUBMIT_JSON")"
           DMG_STATUS="$(python3 -c 'import json,sys; print(json.load(sys.stdin)["status"])' <<<"$DMG_SUBMIT_JSON")"