Monitor Snowflake Cortex agents by version

Agent Observability now captures which version of a Snowflake Cortex agent handled each run. Version is available as a segment-by field on agent metric monitors and evaluation monitors, so a single monitor can track latency, tokens, errors, or eval scores per version instead of blending them into one line. It also appears in trace metadata, so you can see which version produced any given trace.

A Cortex version commit can swap tools, instructions, and the orchestration model at once. Previously every version collapsed into a single time-series, so a regression after a release showed up as an unexplained blip. Now it shows up as a divergence between versions, and you can confirm a new version is actually better before promoting it.