UI capability update: large diffs not rendered by default (Updates #2623)

AI Impact Summary

The CAPABILITY change signals an adjustment to how the platform renders diffs in the UI. The source content indicates that large diffs are not rendered by default and certain actions are blocked, suggesting a frontend rendering limit or incremental loading behavior has been introduced. For teams relying on full-diff visibility in code review or automated tooling, this may require changes to workflows or tooling to handle split or lazy-loaded diffs while awaiting any new flags or configurations that enable full rendering.