Add @types/node to showcase examples and ensure declaration files are generated

Co-authored-by: hotlong <50353452+hotlong@users.noreply.github.com>

Author: Copilot

examples/showcase/enterprise-erp/package.json

@@ -45,6 +45,7 @@
     "@objectql/platform-node": "workspace:*",
     "@objectstack/spec": "^0.2.0",
     "@types/jest": "^30.0.0",
+    "@types/node": "^20.0.0",
     "jest": "^30.2.0",
     "ts-jest": "^29.4.6",
     "typescript": "^5.3.0"

examples/showcase/project-tracker/package.json

@@ -46,6 +46,7 @@
     "@objectql/platform-node": "workspace:*",
     "@objectql/types": "workspace:*",
     "@types/jest": "^30.0.0",
+    "@types/node": "^20.0.0",
     "jest": "^30.2.0",
     "ts-jest": "^29.4.6",
     "typescript": "^5.3.0"