Add support to run on startup

[intercepted16]

Please add support to run on startup. ~I haven't tested but I believe I could manually do this by running the portable executable hidden on startup, although this is rather cumbersome.~

~Edit: it seems that there is no bundled Neptune CLI for Windows, so even the solution I proposed above is not possible.~

Edit: just read the docs again, turns out Neptune GUI is bundled with Neptune CLI. Created a scheduled task using run-hidden.exe manually. Works fine. Though I'd still like to see this built in.