fix: app icon not displaying in Finder and DMG (#41)

- Add CFBundleIconName to Info.plist alongside CFBundleIconFile — modern
  macOS requires both keys for the icon to render in Finder
- Fix @2x icon DPI from 72 to 144 for proper Retina display support

Author: jatinkrmalik

Sources/VocaMac/Resources/AppIcon.icns

@@ -92,6 +92,8 @@ cat > "${APP_DIR}/Contents/Info.plist" << EOF
     <true/>
     <key>CFBundleIconFile</key>
     <string>AppIcon</string>
+    <key>CFBundleIconName</key>
+    <string>AppIcon</string>
     <key>NSMicrophoneUsageDescription</key>
     <string>VocaMac needs microphone access to capture your voice for transcription.</string>
     <key>NSPrincipalClass</key>