List all my instances

Show my running VPS and node instances

## Instances for 0x1234...abcd

Found 2 instance(s):

### VPS: vps-xs (my-server)
- **ID:** inst_456
- **Status:** ✅ active
- **Renewable:** ✅ Yes
- **Start:** 1/15/2025
- **End:** 4/15/2025

### NODE: eigenlayer
- **ID:** inst_789
- **Status:** ✅ active
- **Renewable:** ✅ Yes
- **Start:** 1/10/2025
- **End:** 2/10/2025

> Use `get_instance` with an instance ID to get connection details (IP, credentials).