Release v0.7.0

[brendancol]

Summary

• Update CHANGELOG.md for the v0.7.0 release (2026-03-02)
• 12 new features including hydrology tools, terrain metrics (TRI/TPI/Roughness), surface distance, 3D multi-band focal, GPU polygonize with CCL, emerging hotspots, and expanded dask+cupy backends
• 9 bug fixes and improvements covering OOM guards, input validation, dask-safe helpers, and lazy backend loading

After merge

git tag -a v0.7.0 -s -m "Version 0.7.0"
git push --tags

PyPI publish, docs, and conda-forge will follow automatically.