OpenRouter encrypted reasoning metadata can be dropped on empty replay

[nicko-ai]

OpenRouter encrypted reasoning metadata can be lost when an empty reasoning replay closes the reasoning item before response.output_item.done arrives.

Expected behavior:

• encrypted reasoning stays open until the final response.output_item.done event
• final encrypted_content is preserved in reasoning metadata
• the reasoning part closes once

Actual behavior:

• an empty reasoning_item_created replay can close the item early
• the later output_item.done metadata is ignored because the reasoning part is no longer open