refactor(db): streamline model imports and remove unused model exports

- Removed the export of models from the database connection module to simplify the structure.
- Updated various files to import models directly from the new centralized models module.
- Ensured consistency across the codebase by replacing mongoose model references with the new import paths.

api/db/index.js

@@ -3,6 +3,6 @@ const { createModels } = require('@librechat/data-schemas');
 const { connectDb } = require('./connect');
 const indexSync = require('./indexSync');
 
-const models = createModels(mongoose);
+createModels(mongoose);
 
-module.exports = { connectDb, indexSync, ...models };
+module.exports = { connectDb, indexSync };

api/db/indexSync.js

@@ -1,8 +1,9 @@
 const mongoose = require('mongoose');
 const { MeiliSearch } = require('meilisearch');
-const { isEnabled } = require('~/server/utils');
 const { logger } = require('@librechat/data-schemas');
 
+const { isEnabled } = require('~/server/utils');
+
 const Conversation = mongoose.models.Conversation;
 const Message = mongoose.models.Message;
 

api/db/models.js

@@ -0,0 +1,5 @@
+const mongoose = require('mongoose');
+const { createModels } = require('@librechat/data-schemas');
+const models = createModels(mongoose);
+
+module.exports = { ...models };