Create a transformation script to map Solr fields to Fess fields:

```python
import json

# Load Solr export
with open('solr-export.json', 'r') as f:
    solr_data = json.load(f)

# Transform documents
fess_docs = []
for doc in solr_data['response']['docs']:
    fess_doc = {
        "url": doc.get("id", ""),
        "title": doc.get("title", [""])[0] if isinstance(doc.get("title"), list) else doc.get("title", ""),