feat: make reverse proxy operator-managed

backend/src/test/resources/spa-fixture/assets/app.js

@@ -0,0 +1 @@
+window.__KAIDI_SPA_FIXTURE__ = 'kaidi-spa-fixture';

backend/src/test/resources/spa-fixture/index.html

@@ -0,0 +1,5 @@
+<!doctype html>
+<html lang="zh-CN">
+  <head><meta charset="UTF-8"><title>kaidi-spa-fixture</title></head>
+  <body><div id="app">kaidi-spa-fixture</div></body>
+</html>