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.

server/utils/suggestions.js

@@ -108,19 +108,36 @@ export async function suggestNetworkIPAM(opts = {}) {
 
 /**
  * Host ports published by containers.
+ * Includes per-port owners so clients can ignore the source container when
+ * duplicating (swap) without false host-port conflicts.
  */
 export async function listUsedHostPorts() {
   const containers = await docker.listContainers({ all: true })
   /** @type {Set<number>} */
   const ports = new Set()
+  /** @type {{ port: number, protocol: string, id: string, name: string }[]} */
+  const owners = []
   for (const c of containers) {
+    const id = String(c.Id || '')
+    const name = String(c.Names?.[0] || '')
+      .replace(/^\//, '') || id.slice(0, 12)
     for (const p of c.Ports || []) {
-      if (p.PublicPort) ports.add(Number(p.PublicPort))
+      if (!p?.PublicPort) continue
+      const port = Number(p.PublicPort)
+      if (!Number.isFinite(port)) continue
+      ports.add(port)
+      owners.push({
+        port,
+        protocol: String(p.Type || 'tcp').toLowerCase() === 'udp' ? 'udp' : 'tcp',
+        id,
+        name,
+      })
     }
   }
   return {
     success: true,
     ports: [...ports].sort((a, b) => a - b),
+    owners,
   }
 }