I just noticed that these commands are missing from the Message-menu and the related commands (Cmd-Ctrl-G and (Cmd-Ctrl-S) are not working although both Mail and SpamSieve are open and the extension is active.
macOS 15.0.1 (24A348) · MacBookPro M2
Mail.app 16.0 (3818.100.11.1.3)
SpamSieve 3.05
SpamSieve only adds commands to Message menu in Apple Mail on macOS 13 Ventura and earlier. On macOS Sonoma and Sequoia they are in SpamSieve menu bar icon and in the Dock menu:
Please make sure that you are able to use the menu commands, and then we can troubleshoot the keyboard shortcuts if necessary.