Update dependency neo4j to v6

Author: renovate[bot]

conda-environment.yml

@@ -25,4 +25,4 @@ dependencies:
   - umap-learn=0.5.9 # to visualize node embeddings in 2D (UMAP dimensionality reduction)
   - shap=0.48.0
   - pip:
-      - neo4j==5.28.2
+      - neo4j==6.1.0

requirements.txt

@@ -24,7 +24,7 @@ optuna==4.6.0
 umap-learn==0.5.9.post2 # Dimensionality reduction to visualize node embeddings in 2D
 
 # --- Database connector ---
-neo4j==5.28.2
+neo4j==6.1.0
 
 # --- Native/scientific packages (may require compilation) ---
 # These are included but may cause install errors in pip/venv