refactor: migrate database layer to Prisma ORM

package.json

@@ -28,14 +28,15 @@
     "@nestjs/passport": "^11.0.5",
     "@nestjs/platform-express": "^11.1.13",
     "@nestjs/serve-static": "^5.0.4",
+    "@prisma/client": "^6.19.2",
     "bcryptjs": "^3.0.3",
-    "better-sqlite3": "^12.6.2",
     "class-transformer": "^0.5.1",
     "class-validator": "^0.14.3",
     "dotenv": "^17.2.3",
     "jsonwebtoken": "^9.0.2",
     "passport": "^0.7.0",
     "passport-jwt": "^4.0.1",
+    "prisma": "^6.19.2",
     "qrcode": "^1.5.4",
     "reflect-metadata": "^0.2.2",
     "rxjs": "^7.8.2"
@@ -44,7 +45,6 @@
     "@nestjs/cli": "^11.0.0",
     "@nestjs/schematics": "^11.0.0",
     "@nestjs/testing": "^11.1.13",
-    "@types/better-sqlite3": "^7.6.13",
     "@types/express": "^5.0.6",
     "@types/jest": "^30.0.0",
     "@types/jsonwebtoken": "^9.0.10",