Investigate the best approach for handling potential underflow in __wt_btree_decrease_size when dealing with disaggregated storage delta chain accounting during reconciliation failures.

The function __wt_btree_decrease_size currently uses a 0 clamp to prevent underflow. This occurs during reconciliation failures when the entire delta chain is discarded from storage, causing bytes_total to decrease by cumulative size while individual delta sizes were previously added.

Technical context of reconciliation failures:

1. Page is marked with WT_BLOCK_INVALID_PAGE_ID
2. Entire delta chain is discarded from storage
3. Next reconciliation writes full page image with new page_id
4. This creates temporary accounting "mismatch" that appears as underflow

As part of this investigation:

• Determine the most robust and maintainable approach for handling this accounting scenario
• Either justify the current 0 clamp as optimal, or propose a better alternative
• Provide clear documentation of the chosen approach and its rationale
• Consider whether the assert can be safely re-enabled with modifications