feat: Introduce knex for database migrations

- Adds knex.js to manage database schema changes systematically.
- Creates an initial migration file based on `hyungi_schema_v2.sql` to represent the current database state.
- Adds npm scripts (`db:migrate`, `db:rollback`, etc.) for easy execution of migration tasks.
- Archives legacy SQL files and old migration scripts into the `db_archive/` directory to prevent confusion and clean up the project structure.

api.hyungi.net/package.json

@@ -4,7 +4,18 @@
   "main": "index.js",
   "scripts": {
     "start": "pm2-runtime start ecosystem.config.js --env production",
-    "dev": "pm2-runtime start ecosystem.config.js --env development"
+    "dev": "pm2-runtime start ecosystem.config.js --env development",
+    "test": "jest",
+    "test:watch": "jest --watch",
+    "test:coverage": "jest --coverage",
+    "test:unit": "jest tests/unit",
+    "test:integration": "jest tests/integration",
+    "test:verbose": "jest --verbose",
+    "db:migrate": "knex migrate:latest --knexfile knexfile.js",
+    "db:migrate:make": "knex migrate:make --knexfile knexfile.js",
+    "db:rollback": "knex migrate:rollback --knexfile knexfile.js",
+    "db:seed": "knex seed:run --knexfile knexfile.js",
+    "db:seed:make": "knex seed:make --knexfile knexfile.js"
   },
   "dependencies": {
     "@simplewebauthn/server": "^13.1.1",
@@ -19,6 +30,7 @@
     "express-validator": "^7.2.1",
     "helmet": "^7.2.0",
     "jsonwebtoken": "^9.0.0",
+    "knex": "^3.1.0",
     "multer": "^1.4.5-lts.1",
     "mysql2": "^3.14.1",
     "node-cache": "^5.1.2",
@@ -28,5 +40,10 @@
     "sqlite3": "^5.1.6",
     "swagger-jsdoc": "^6.2.8",
     "swagger-ui-express": "^5.0.1"
+  },
+  "devDependencies": {
+    "@types/jest": "^29.5.12",
+    "jest": "^29.7.0",
+    "supertest": "^7.0.0"
   }
 }