Fix Docker image build failures

[iandees]

Summary

• Removed gdal == 3.7.1 from pip install_requires — GDAL is provided by the base Docker image and can't be built from PyPI on Alpine (missing osgeo source directory)
• Loosened Shapely == 2.0.1 to >= 2.0.1 — the pinned version has no pre-built wheel for Alpine/musl and fails to build due to missing pkg_resources
• Updated mapbox-vector-tile from 2.0.1 to 2.1.0 — the old version required protobuf<5.0, conflicting with protobuf==5.29.6

Fixes #90

Test plan

• docker build --no-cache -t batch-machine . completes successfully

🤖 Generated with Claude Code

[iandees]

Closing in favor of #91 which takes a more conservative approach (reverting the protobuf bump instead of upgrading mapbox-vector-tile).