Tweak animated globe hero: camera angle, speed, styling

[rdhyee]

First pass shipped in PR #69. Capture tooling in PR #76 (tools/).

Tweaks needed

• Globe sits slightly low — adjust camera pitch
• Rotation speed (currently 15s/loop) — may need further tuning
• Starting view angle
• File size optimization (currently 3.8 MB)
• Consider "click to explore" overlay

Re-capture workflow

python -m http.server 8765 --directory tools/
python tools/capture_globe_rotation.py [--duration 15] [--quality 40]
cp /tmp/isamples_globe.webp assets/isamples_globe.webp