Update to latest Svelte and Sveltekit

[mhkeller]

Now that Svelte 5 is in Release Candidate mode, it would be great to update this to use the latest and also show am the proper way to serve different html pages. There also have been some changes with Electron 30 that would be great to reflect.

Let me know if you need any help.

[mhkeller]

I ended up making a fresh version here with a couple of different options serving the pages either with mainWindow.loadFile or using electron-serve: https://github.com/mhkeller/sveltekit-electron

[ghostdevv]

Sorry neither of us have had a chance to get to this - feel free to submit a PR with updates and I'll take a look!