style: clean up code formatting and remove trailing whitespace

refactor: reorganize imports and fix type imports

lib/mongodb/connection.ts

@@ -3,7 +3,7 @@
  * Singleton pattern para reutilizar conexão
  */
 
-import mongoose from "mongoose";
+import type mongoose from "mongoose";
 
 function getMongoUrl(): string {
   const url = process.env.MONGO_URL;
@@ -24,7 +24,7 @@ declare global {
   var mongoose: MongooseCache | undefined;
 }
 
-let cached: MongooseCache = global.mongoose || { conn: null, promise: null };
+const cached: MongooseCache = global.mongoose || { conn: null, promise: null };
 
 if (!global.mongoose) {
   global.mongoose = cached;
@@ -79,4 +79,3 @@ export async function disconnectMongoDB(): Promise<void> {
     cached.promise = null;
   }
 }
-