feat: bind operator sessions to upstream identity (Closes #1372)

frontend/login.js

@@ -119,7 +119,7 @@
       return;
     }
     if (reason === 'session-idle') {
-      status.textContent = 'Stackchain locked after inactivity. Your drafts and queued work are still on this device. Sign in to resume.';
+      status.textContent = 'Stackchain locked. Your drafts and queued work are still on this device. Sign in to resume.';
       return;
     }
     if (reason !== 'session-revoked') return;