Refactor server state and add health checks

webui/swagger.html

@@ -18,6 +18,7 @@
         </div>
         <nav class="nav-links">
           <a class="nav-link" href="/openapi.json">openapi.json</a>
+          <a class="nav-link" href="/health">Health</a>
           <a class="nav-link" href="/viewer">Message Viewer</a>
         </nav>
       </aside>