Spark: Emit geometry bounds in Parquet writers

[huan233usc]

Spark 4.1 and 4.2 Parquet writers currently emit value-size metrics for geometry but omit its spatial bounds. Keep the shared geospatial WKB write path and let each private writer update its existing metrics builder: geometry uses GeometryFieldMetrics.Builder for XY bounds, while geography retains size-only metrics. Preserve the CRS from the Parquet annotation, null counts, and byte totals. Spark 4.2 continues to slice the original WKB payload to preserve byte order. Core metrics classes and public APIs are unchanged.

Test plan:

• 55 tests: core metrics (7), Parquet writers/file metrics (30), and Spark TestSparkParquetWriter on 4.1 and 4.2 (9 each). Covers file bounds, null/empty inputs, CRS, byte totals, and WKB round-trips.
• Modified modules: assemble, spotlessCheck, checkstyleMain, and checkstyleTest.

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AI Disclosure

• Model: GPT-6
• Platform/Tool: Codex
• Human Oversight: reviewed
• Prompt Summary: Implement geometry bounds emission in Spark 4.1/4.2 while preserving the common GeospatialWriter path.
• Generated content: Writer integration and regression tests.