Add animated menu bar icon when runners are active

[Peyton-Spencer]

Feature Request

Add visual feedback to the menu bar icon to show when runners are active/running.

Proposed Behavior

• Static icon (current default): When all runners are stopped or idle
• Animated icon (running man animation): When one or more runners are actively running

Why This Helps

Currently, you need to click the menu bar icon to see runner status. An animated icon provides instant visual feedback from the menu bar, making it easy to see at a glance when runners are active without any interaction.

Implementation Notes

• macOS supports animated menu bar icons via NSStatusItem
• Can use an animated SF Symbol or sequence of custom images
• Animation should be subtle but noticeable
• Should pause animation when all runners stop

References

Similar to:

• Dropbox (sync animation)
• iStat Menus (activity indicators)
• Docker Desktop (running whale animation)