fix: increase Neo4j memory limits to resolve transaction threshold error

Add NEO4J_dbms_memory_transaction_total_max=4G and
NEO4J_server_memory_heap_max__size=4G to prevent
"dbms.memory.transaction.total.max threshold reached" errors.

docker-compose.override.yml

@@ -16,6 +16,12 @@ services:
       - SYS_MODULE
     restart: unless-stopped
 
+  # === Neo4j memory tuning ===
+  database:
+    environment:
+      - NEO4J_dbms_memory_transaction_total_max=4G
+      - NEO4J_server_memory_heap_max__size=4G
+
   # === Infrahub ===  
   message-queue:
     ports: !override
@@ -28,4 +34,4 @@ services:
       []
 
 volumes:
-  tailscale-state:
+  tailscale-state: