The package-lock.json is missing platform-specific optional dependencies
(like fsevents, @parcel/watcher-*, @esbuild/* packages) because it was
generated on Linux. npm ci is strict and fails when these are missing.

Using npm install --prefer-offline instead allows the build to proceed
while still respecting the lock file for version resolution.

localStorage is not available in Node.js test environment.
Added checks to prevent accessing localStorage when it's undefined,
which fixes the 'localStorage.getItem is not a function' test errors.

Mock localStorage in test setup to fix 'localStorage.getItem is not a function' errors.
The happy-dom environment doesn't provide a fully functional localStorage by default.

Add typeof check for localStorage.getItem to handle cases where localStorage
exists but doesn't have the getItem method (can happen during test setup timing).

Add missing Storage interface properties (key, length) to make the mock
fully compatible with the Storage type.

UI fixes