redesign: move 8junio to cronicas/, update map coloring and stats

- Relocate 8junio/8junio.html → cronicas/8junio/8junio.html
- Color map markers by absolute temperature (18.5–19.5°C) instead of anomaly
- Add spatial range stat (max − min = 0.8°C)
- Update narrative and legend accordingly
- Update index.html link to new path

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: ignasivalles