fix: 服务发现排除前端已注册的自定义服务

- API 新增 exclude_ports 查询参数，接受逗号分隔端口列表
- 前端 scanServices() 读取 localStorage 自定义服务端口传给后端
- 已添加的服务不再出现在扫描结果中

templates_full.txt

@@ -2886,7 +2886,12 @@
             list.innerHTML = '<div class="text-gray-400 text-xs text-center py-2"><i class="ri-loader-4-line animate-spin"></i> 扫描中...</div>';
             
             try {
-                const res = await fetch('/api/discovery/services');
+                // 收集前端已注册的自定义服务端口，传给后端排除
+                const customServices = getCustomServices();
+                const customPorts = customServices.map(s => parseInt(s.port)).filter(p => !isNaN(p));
+                const excludeParam = customPorts.length > 0 ? `?exclude_ports=${customPorts.join(',')}` : '';
+                
+                const res = await fetch(`/api/discovery/services${excludeParam}`);
                 const data = await res.json();
                 const services = data.services || [];
                 document.getElementById('discoveryCount').textContent = `发现 ${services.length} 个`;