feat: 统一服务缓存 + 指纹驱动插件匹配

将 webServiceCache 扩展为通用 serviceCache，所有指纹识别结果
统一缓存，插件匹配时端口不命中则回退到服务名称匹配。

删除多余的 service_cache.go，复用已有的 ServiceInfo 体系。
补充 nil 防御、Explicit 标记、大量单元/集成/回归测试。

libs/grdp/login/screen.go

@@ -176,8 +176,7 @@ func (g *Client) ProbeOSInfo(host, domain, user, pwd string, timeout int64, rdpP
 	exitFlag := make(chan bool, 1)
 	info = make(map[string]any)
 
-	targetSlice := strings.Split(g.Host, ":")
-	ip := targetSlice[0]
+	ip := rdpTargetHost(g.Host)
 	conn, err := WrapperTcpWithTimeout("tcp", g.Host, time.Duration(timeout)*time.Second)
 	if err != nil {
 		return
@@ -273,3 +272,14 @@ loop:
 	glog.Debug("loop ended, elapsed time: ", time.Since(start))
 	return info
 }
+
+func rdpTargetHost(target string) string {
+	host, _, err := net.SplitHostPort(target)
+	if err == nil {
+		return host
+	}
+	if strings.Count(target, ":") == 1 {
+		return strings.SplitN(target, ":", 2)[0]
+	}
+	return target
+}

libs/grdp/login/screen_test.go

@@ -0,0 +1,24 @@
+package login
+
+import "testing"
+
+func TestRDPTargetHost(t *testing.T) {
+	tests := []struct {
+		name   string
+		target string
+		want   string
+	}{
+		{name: "ipv4 with port", target: "192.168.1.1:3389", want: "192.168.1.1"},
+		{name: "hostname with port", target: "rdp.example.com:3389", want: "rdp.example.com"},
+		{name: "bracketed ipv6 with port", target: "[2001:db8::1]:3389", want: "2001:db8::1"},
+		{name: "bare ipv6 without port", target: "2001:db8::1", want: "2001:db8::1"},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := rdpTargetHost(tt.target); got != tt.want {
+				t.Fatalf("rdpTargetHost(%q) = %q, want %q", tt.target, got, tt.want)
+			}
+		})
+	}
+}