refactor: rename server-configs.json to servers.json and update related references

backend/routes/serverConfigsRoutes.js

@@ -10,7 +10,7 @@ const { createJsonDataRoutes } = require('./jsonDataRoutes');
 const { getS3TextWithHeaders, getS3JsonWithHeaders } = require('../utils/s3Helpers');
 
 // GET /api/server-configs (список серверов)
-const serverConfigsListRoutes = createJsonDataRoutes('server-configs.json', (server, i) => {
+const serverConfigsListRoutes = createJsonDataRoutes('servers.json', (server, i) => {
   if (!server.id || !server.name) {
     return `Server at index ${i} is missing required fields`;
   }