refactor: comprehensive code quality improvements and dev environment fixes

- Convert ProcessingStatusManager from static class to individual functions
- Refactor processSingleImport function to reduce cognitive complexity
- Fix unused parameters in database-pool.ts event handlers
- Add missing DATABASE_URL configuration to env.ts
- Add pg package and @types/pg dependencies for PostgreSQL support
- Fix tsx command execution by updating package.json scripts to use pnpm exec
- Apply biome formatting fixes for import organization

package.json

@@ -5,7 +5,7 @@
   "private": true,
   "scripts": {
     "build": "next build",
-    "dev": "tsx server.ts",
+    "dev": "pnpm exec tsx server.ts",
     "dev:next-only": "next dev --turbopack",
     "format": "npx prettier --write .",
     "format:check": "npx prettier --check .",
@@ -17,12 +17,12 @@
     "biome:lint": "biome lint .",
     "prisma:generate": "prisma generate",
     "prisma:migrate": "prisma migrate dev",
-    "prisma:seed": "tsx prisma/seed.ts",
-    "prisma:seed:platform": "tsx prisma/seed-platform.ts",
+    "prisma:seed": "pnpm exec tsx prisma/seed.ts",
+    "prisma:seed:platform": "pnpm exec tsx prisma/seed-platform.ts",
     "prisma:push": "prisma db push",
     "prisma:push:force": "prisma db push --force-reset",
     "prisma:studio": "prisma studio",
-    "db:check": "tsx scripts/check-database-config.ts",
+    "db:check": "pnpm exec tsx scripts/check-database-config.ts",
     "start": "node server.mjs",
     "test": "concurrently 'vitest run' 'playwright test'",
     "test:coverage": "concurrently \"vitest run --coverage\" \"echo 'To add playwright coverage thingy'\"",
@@ -79,6 +79,7 @@
     "next-themes": "^0.4.6",
     "node-cron": "^4.1.1",
     "node-fetch": "^3.3.2",
+    "pg": "^8.16.3",
     "react": "^19.1.0",
     "react-day-picker": "^9.7.0",
     "react-dom": "^19.1.0",
@@ -101,6 +102,7 @@
     "@testing-library/react": "^16.3.0",
     "@types/node": "^24.0.6",
     "@types/node-cron": "^3.0.11",
+    "@types/pg": "^8.15.4",
     "@types/react": "^19.1.8",
     "@types/react-dom": "^19.1.6",
     "@typescript-eslint/eslint-plugin": "^8.35.0",