20.21.1 (2026-10-12) Bug Fixes improve span ingestion reliability (#16889) (678740c) trace: accept empty dataframes in TraceDataset (#16913) (d0dc9e5) Documentation Add Scalekit to the Phoenix platform docs (#16896) (1afe1ea) readme: make the "Add to Cursor" MCP badge clickable on GitHub (#16926) (b8d0e3f)