Park source container on duplicate so host ports can be reused

When duplicating with the same host ports, stop+rename the origin, deploy
and verify the new container, then remove the parked source. Client
precheck ignores ports owned only by the origin to avoid false blocks.

app.js

@@ -12569,7 +12569,10 @@ async function openDuplicateModal(container) {
       // ignore
     }
 
-    populateDuplicateForm(config, { existingNames });
+    populateDuplicateForm(config, {
+      existingNames,
+      sourceContainerId: container.Id || config.Id || '',
+    });
     setupDeployResourceSliders();
 
     const networkMode = document.getElementById('duplicate-network-mode');