feat: add persistent desktop assistant workspace

Co-authored-by: factory-droid[bot] <138933559+factory-droid[bot]@users.noreply.github.com>

src/main/agent/loopback-port.ts

@@ -0,0 +1,23 @@
+import { createServer } from 'node:net'
+
+export async function getAvailableLoopbackPort(): Promise<number> {
+  return new Promise<number>((resolvePort, reject) => {
+    const server = createServer()
+    server.unref()
+    server.once('error', reject)
+    server.listen(0, '127.0.0.1', () => {
+      const address = server.address()
+      const port =
+        address && typeof address === 'object' ? address.port : 0
+      server.close((error) => {
+        if (error) {
+          reject(error)
+        } else if (port > 0) {
+          resolvePort(port)
+        } else {
+          reject(new Error('无法分配本机端口'))
+        }
+      })
+    })
+  })
+}