Clearer logs for every agent run

Agent logs are now much easier to read.

Logs show each run as a timeline with steps, live progress, generated documents, errors, and summaries of what happened.

Errors can include expandable details and a path back to the agent chat, so you can ask the agent to explain or fix the problem.

Logs also support markdown and richer output, which makes long-running or complex agents easier to monitor and debug.