Add info tooltip explaining 'Running' agent status

[GalDayan]

Current behavior:
"Running" status shown on agents with no explanation

Problem:
Users don't understand what "Running" means vs other statuses

Expected:

• Add (i) info icon next to "Running" status
• Tooltip on hover explaining:
  • What "Running" means (active session with messages in last X minutes)
  • How it differs from "Idle", "Completed", etc.
  • When status updates

Priority: P2 - UX improvement