Add confined host escalation transport

crates/lazaret-host-coordinator/src/control.rs

@@ -289,6 +289,11 @@ impl TrustAnchor {
         }
     }
 
+    #[must_use]
+    pub fn coordinator_protocol_key(&self) -> SigningKey {
+        self.coordinator_protocol_key.clone()
+    }
+
     /// Transfers the sandbox credential package once without exposing coordinator or issuer keys.
     ///
     /// # Errors