feat(db): add PostgreSqlService with pg driver

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

package.json

@@ -48,6 +48,7 @@
     "lucide-react": "^0.575.0",
     "mssql": "^12.2.0",
     "mysql2": "^3.18.2",
+    "pg": "^8.20.0",
     "playwright": "^1.58.2",
     "playwright-core": "^1.58.2",
     "react-focus-lock": "^2.13.7",
@@ -72,6 +73,7 @@
     "@playwright/test": "^1.58.2",
     "@types/mssql": "^9.1.9",
     "@types/node": "^22.19.13",
+    "@types/pg": "^8.20.0",
     "@types/react": "^19.2.7",
     "@types/react-dom": "^19.2.3",
     "@types/uuid": "^10.0.0",