Validate native geometry values on import - #9180

Summary

• validate Point, list-based geometry, and Rect values once at the GeoArrow-to-native boundary
• preserve GeoArrow empty-Point, slice, and null-parent semantics while rejecting malformed or non-finite X/Y values
• validate WKB literals after decoding to native buffers without eagerly parsing stored WKB columns
• benchmark the incremental cost with paired validation-disabled and validation-enabled import paths

Validation policy

• Point: all-NaN ordinates represent empty; otherwise X/Y must be finite
• List geometries: every reachable X/Y coordinate must be finite
• Rect: X/Y bounds must be finite and ordered
• Z/M remain outside the current 2-D validity policy
• child values beneath null geometry rows are ignored

Validation overhead benchmark

Each pair uses identical Arrow arrays, storage conversion, and extension wrapping. The only added work in With is the production validator.

The high Point and Rect ratios compare a full buffer scan with a sub-microsecond zero-copy wrapper that never reads coordinate data. Over roughly one million coordinates or rows, the absolute validation cost is about 0.18-0.47 ns per coordinate/row, with 53-91 GB/s dense scan throughput. Sparse Point is slower because its regular null pattern creates about 105,000 short valid runs.