📌 Summary

Adding an option to include an NCBI API key in the .env file to improve rate limiting.

🔄 Type of Change

• 🐛 Bug fix (non-breaking change that fixes an issue)
• ✨ New feature (non-breaking change that adds functionality)
• 💥 Breaking change (fix or feature that would cause existing functionality to change)
• 🧹 Refactor (code change that neither fixes a bug nor adds a feature)
• 📚 Documentation update
• ⚙️ CI / build / tooling change

🧩 Key Changes

• adding an option for using an NCBI API key for taxonomic lookups
• updating key name to ncbi_api_key
• adding a guard to only apply the key in the API request parameters if a key has been provided

✅ Checklist

• Tests are passing locally / in CI
• New tests have been added for new or changed functionality
• Self-review completed
• Documentation updated (if needed)
• No sensitive data or secrets included

🔍 Review Notes

📎 Related Issues / Tickets

• Closes #
• Related to #