* epub-document.c: Fix null pointer crash when building a TOC.
* ev-window.c: Check that we have a document set before accessing it.
* ev-sidebar-thumbnails.c: Don't attempt to generate thumbnails for epub docs.
* Update private.h: gcc-15 build fix (#667)
* epub: Disable support for sidebar thumbnails. (#671)
OBS-URL: https://build.opensuse.org/package/show/X11:Cinnamon:Factory/xreader?expand=0&rev=97
