Feature Request: Show session status (running/pending/completed) in session list

Problem

When multiple sessions are open, the session list sidebar only shows timestamps — there is no way to tell which sessions are currently running, waiting for input, or completed.

This becomes a significant pain point when running parallel agents or background tasks across multiple sessions, as you must click into each session individually to check its status.

Proposed Solution

Add a status indicator/badge to each session in the sidebar list:

• 🟢 Running — Claude is actively processing
• 🟡 Waiting — waiting for user input
• ✅ Completed — last turn finished, no pending work
• 🔵 Idle — session open but no recent activity

Expected Behavior

Users should be able to glance at the session list and immediately understand which sessions need attention, which are still processing, and which have finished — without having to click into each one.

Additional Context

This is especially useful for power users managing multiple parallel agent sessions simultaneously. Right now the only workaround is clicking into each session to check for loading spinners or read the last message.