0.3.0 release validation
PASS: fresh empty onboarding, optional read-only sample, explicit sample import protection.
PASS: 0.2.0 data initialization upgrade preserves all fixture bytes; backup exact; concurrent initialization.
PASS: Debian .run install, paths with spaces, shortcut, Pi .run upgrade on Debian, backup, uninstall preserves data.
PASS: old/mixed/segmented layouts, 19 sample zones, coordinate and point-count validation, saved layout round trips.
PASS: builder blank-label defaults, empty segment handling, single-point rejection, save failure/retry, browser draft restoration.
PASS: preview separate paths, zone selection, chase/fade/blink/off, stop, automatic state, editor access after automatic mode.
PASS: real HTTP launch, create/update/reload show, multi-color chase, duplicate-show protection, segmented save/reopen.
PASS: browser clean onboarding and empty zone planner.
PASS: Windows NSIS installer compilation.
NOT TESTED: native Windows installation/upgrade/uninstall; Raspberry Pi ARM hardware; physical light output (not implemented).
