The desktop app now manages the shared AC credential the whole suite reads. Tray Account section: status (signed in as @handle / expired / signed out), 'Sign in to Aesthetic Computer' and 'Sign out' run the existing ac-login CLI (tezos/ac-login.mjs) under Electron's bundled node (ELECTRON_RUN_AS_NODE), writing ~/.ac-token. Identity shows the @handle only (token is an encrypted JWE; the file's user.handle is used). DateWizard + ac-os already read the same token; this makes one sign-in serve every AC app.