curl -s -X POST "http://127.0.0.1:3000/v1/users/user_123/graph/edges" \
  -H "Authorization: Bearer $TOKEN" \
  -H "Content-Type: application/json" \
  -d '{
    "source_id": "11111111-1111-1111-1111-111111111111",
    "target_id": "22222222-2222-2222-2222-222222222222",
    "relation": "RelatedTo",
    "weight": 0.75
  }'