feat(onboarding): backend api for onboarding users

backend/src/config/serverConfig.ts

@@ -0,0 +1,24 @@
+import { IServerConfig, ServerConfig } from "../models/serverConfig";
+
+let serverConfig: IServerConfig;
+
+export const serverConfigInit = async () => {
+  const cfg = await ServerConfig.findOne({});
+  if (!cfg) {
+    const cfg = new ServerConfig();
+    await cfg.save();
+    serverConfig = cfg;
+  } else {
+    serverConfig = cfg;
+  }
+  return serverConfig;
+};
+
+export const getServerConfig = () => serverConfig;
+
+export const updateServerConfig = async (data: Partial<IServerConfig>) => {
+  const cfg = await ServerConfig.findByIdAndUpdate(serverConfig._id, data, { new: true });
+  if (!cfg) throw new Error("Failed to update server config");
+  serverConfig = cfg;
+  return serverConfig;
+};