New SessionDescriptionEditor renders even when empty (with an "Add a description..." placeholder) and autosaves on typing - same debounced, no-Save-button pattern as the title and device name editors. Unlike the name field, an empty description is a valid saved state. Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01WzyfRyA7h5rs5SCAahLAWd