Christmas Lights Studio 0.3.0

WHAT CHANGED IN 0.3.0
- Start New Segment separates reindeer, arches and other objects within a zone.
- Split before selected point repairs connections in existing outlines.
- Legacy single-outline layouts continue to work.
- Empty segments no longer block saving; labels default to the zone number.
- Save errors and successful server saves are visible. Unsaved drafts can be recovered in the same browser and address when local storage is available.
- Go to Event Editor exits automatic mode before revealing the editor.
- Fresh installs start without sample zones. The sample is an explicit option.
- Upgrades back up existing projects and preserve the separate saved-data folder.

Verification: Debian install/upgrade/uninstall and application regression tests are included with this release. The Windows installer is unsigned and was compiled on Linux; installation on Windows and Raspberry Pi hardware testing are not yet verified.