Adds a floating arc gauge above the central platform that reads from
sovereignty-status.json and displays a color-coded sovereignty score:
- Green (≥80%): fully/mostly sovereign
- Yellow (40–79%): mixed cloud
- Red (<40%): cloud-dependent
Arc fills clockwise from 12 o'clock proportional to score. Gauge
floats at Y≈3.8 with gentle hover animation and glow pulse. Score,
label, and color all driven by sovereignty-status.json stub.
Fixes#203
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
