Animate desktop Octo status header

[pmbstyle]

Summary

• Add animated Octo sprites for idle and thinking desktop dashboard states.
• Reuse one dashboard header across Control, Workers, and System views so status, latest action, and mascot behavior stay consistent.
• Keep thinking animation slower and vertically aligned to avoid visible bouncing.

Validation

• npm run --prefix desktop build

Notes

• Source sprite sheets were left out of the commit so the packaged app only carries the optimized runtime sprites.