fix: remove prepare script to resolve CI failure

The prepare script caused npm ci to fail during Gitea Actions because
it ran 'npm run build' before node_modules/.bin was properly linked,
resulting in 'tsc: not found' errors.

package.json

@@ -17,7 +17,6 @@
     "test:coverage": "jest --coverage",
     "lint": "eslint src/**/*.ts",
     "format": "prettier --write src/**/*.ts",
-    "prepare": "npm run build",
     "dev": "ts-node src/index.ts"
   },
   "keywords": [