Bug fixes and improvements:

KWin Effect:
- Fix effect metadata to resolve "unsupported version" on Debian-based distros
- Convert D-Bus settings loading to async calls (prevents compositor blocking)
- Address PR review issues in async D-Bus handling

Window Management:
- Persist pre-snap geometry across window close/reopen cycles

Autotiling & KCM:
- Add autotiling settings page with algorithm preview
- Hide autotile layouts when autotiling disabled
- Fix zone selector updates on settings changes
- Fix overlay refresh on autotile setting changes
- Improve algorithm preview centering and monocle detection

Packaging:
- Simplify CI pipeline (single Arch build)
- Move packaging files to packaging/ directory
- Enable debug symbol packages for all distros