feat: calculate used storage

prisma/migrations/20250410130313_add_storage/migration.sql

@@ -0,0 +1,10 @@
+/*
+  Warnings:
+
+  - You are about to drop the column `image` on the `users` table. All the data in the column will be lost.
+
+*/
+-- AlterTable
+ALTER TABLE "users" DROP COLUMN "image",
+ADD COLUMN     "storage_used" INTEGER DEFAULT 0,
+ADD COLUMN     "token_balance" INTEGER DEFAULT 0;