Fixes a broken AppImage. On any machine using Mesa graphics (Intel, AMD, Nouveau) the window came up empty and nothing worked: the bundle shipped a wayland library older than the one the system's graphics driver needs, so WebKit could not create a display and every web process died at startup. NVIDIA machines were unaffected, which is why this got through testing.
Debian and Ubuntu users also lose the libgvfscommon.so: undefined symbol lines at startup. Same cause, different library: the bundle was overriding host libraries it had no business touching.
The rpm now depends on mpv-libs instead of leaving you to install it by hand.
Release builds now launch the app inside Debian and Arch containers and fail if no webview comes up. The previous checks only verified that the binary linked, which it always did.