Rename websocket /ws → /dougal-websocket.

The Webpack dev server seems to really like /ws and ignores any
attempts to set a different path, so we just rename our websocket
instead.

lib/www/client/source/vue.config.js

@@ -9,7 +9,7 @@ module.exports = {
       "^/api(/|$)": {
         target: "http://127.0.0.1:3000",
       },
-      "^/ws(/|$)": {
+      "^/dougal-websocket(/|$)": {
         target: "ws://127.0.0.1:3000",
         ws: true
       }