Describe the bug
I added a category about, which lists links to Modrinth, Curseforge, Ko-Fi and more. This category has show_category_button: false set and thus can only be opened using a link entry. The entry does not have an unlock condition attached.

When first opening the book, this category is shown (probably since it starts with "a"), instead of the only other unlocked category general.

Expected behavior
Categories with show_category_button: false not being considered for selection on first open. (Unless that's a feature)

Book layout, for reference: https://github.com/DaFuqs/Spectrum/tree/1.21.1-aria-for-painters/src/main/resources/data/spectrum/modonomicon/books/guidebook/categories

EDIT: Setting the sort# of the entry higher than the other entries seems to be a suitable workaround

Yeah the sort num should work around it, but it is not a feature and should be fixed!