Inline Comments on Observation I/O

Anchor comments to specific text selections within trace and observation input, output, and metadata fields. Similar to Google Docs, you can now select text in input, output, or metadata fields, click the hovering comment button, and add comments anchored to that selection. Text-specific comments make it easy to discuss parts of LLM responses and assign them to people via mentions. This feature is available in the "JSON Beta" view.