Add coordinate format normalization for Mask geometry

[paulnoirel]

Description

Add coordinate format normalization for Mask geometry
Ensures consistent GeoJSON coordinate format regardless of shapely version
Shapely 2.0.3 returns lists, 2.0.6+ returns tuples for coordinates
Normalizes to expected GeoJSON structure: list containing tuples
Prevents customer script breakage while supporting all Python versions
Tests pass with original expectations (no test changes needed)
Solves Python 3.13 compatibility without pinning shapely version (2.0.3 incompatibility)

Fixes # (issue)

Type of change

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• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Document change (fix typo or modifying any markdown files, code comments or anything in the examples folder only)

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[kjamrozy]

LGTM