break out ws.go

cmd/server/v1.go

@@ -0,0 +1,15 @@
+package main
+
+import (
+	"fmt"
+	"net/http"
+	"strings"
+)
+
+func isV1(r *http.Request) bool {
+	return strings.HasPrefix(r.URL.Path, "/v1/")
+}
+
+func (s *S) serveV1(w http.ResponseWriter, r *http.Request) error {
+	return fmt.Errorf("not impl: v1")
+}