Feature: Display Cost Estimation per Session (Thread)

[shpoont]

Could you add session (thread) cost estimates?

• Show a compact estimated cost in the left pane (workspaces + sessions list).
• Roll up subagent costs into the parent session total (without double counting).
• If possible, show both values: parent-only cost and parent total including subagents.
• Also add estimated cost visibility in the Agent Activity view.

This would be very helpful for tracking usage and spend while working.

[Samigos]

On it 😎