Improvements to database seeding performance and developer experience.
**Changes:**
1. **Attachment seeding**: Add sample files (PDF, XLSX, PPTX, PNG, ZIP)
to dev seeds with proper file storage
2. **Seeding parallelization**: Process entities within batches in
parallel while respecting dependencies
3. **ORM query logging**: Replace manual logger toggling with
`ORM_QUERY_LOGGING` env var
- Values: `disabled` (default), `server-only` (for local dev), `always`
- Configured once in `core.datasource.ts`, removed from all seeder
services
**For .env:**
```bash
ORM_QUERY_LOGGING=server-only
```
Net result: Faster seeding, cleaner code (-68 lines), better local dev
experience.
