AI review

Changes

• Extracts seed processing into a reusable static method
• Moves _save() call inside the extracted method
• No functional behavior change, just code reorganization
  Potential Risk
  Error handling changed: The original code added seeds, then removed seeds, then saved. If adding succeeds but removing fails, the original code would still save. Now the method does all three in one go - any failure rolls back the whole operation (which is actually safer).
  Verdict
  Low risk - This is a straightforward refactor.