Claude Desktop tray icons are indistinguishable when multiple instances are running

Description:
When multiple Claude Desktop instances are running (e.g., one per account), each instance adds a tray icon — but all tray icons look identical. There is no way to tell:

1. Which tray icon corresponds to the currently open/focused desktop window, or
2. Which tray icon to close when only some instances should be shut down.

Suggested fix:
Add a tooltip on hover for each tray icon that identifies the associated instance (e.g., account name, window title, or PID), so users can confidently pick the correct icon to close without guessing or closing the wrong instance.