packaging: replace com.example.querya_* bundle / application IDs

[ZhuchkaTriplesix]

Parent

Part of #379

Problem

Placeholder IDs (com.example.querya_desktop, com.example.queryaDesktop) drive Linux app-support paths, macOS bundle id, and future desktop entries / uninstall registry. Shipping installable packages on these IDs will force a painful migration later.

Proposal

• Choose final reverse-DNS id (e.g. app.querya.desktop / com.querya.desktop — decide in issue).
• Update Linux APPLICATION_ID, macOS PRODUCT_BUNDLE_IDENTIFIER, Windows version resources.
• Migration note for existing installs: copy/move app-support data from old path, or dual-read once.

Acceptance

• Consistent IDs across Linux / Windows / macOS
• Documented data-path migration for existing users
• Themes/DB still found after upgrade (test plan)
• Done before first public AppImage / deb / setup that embeds the id

References

• linux/CMakeLists.txt
• macos/Runner/Configs/AppInfo.xcconfig
• windows/runner/Runner.rc
• docs/theme-import.md