[GH-2830] Improve Geography query support - functions

[zhangfengcdt]

Did you read the Contributor Guide?

• Yes, I have read the Contributor Rules and Contributor Development Guide

Is this PR related to a ticket?

• Yes, and the PR name follows the format [GH-XXX] my subject. Closes #<issue_number>

What changes were proposed in this PR?

Implements WKB-based Geography serialization (Option B: WKB with Cached S2) and a full set of Geography ST functions.

Core architecture:

• WKBGeography — stores WKB bytes as primary representation with lazy-parsed JTS, S2, and ShapeIndex caches (double-checked locking for thread safety)
• GeographyWKBSerializer — WKB serializer with 0xFF format byte, backward-compatible with legacy S2-native format
• GeographyUDT, implicits.scala, GeometrySerde — switched to WKBSerializer for all serialization paths

Geography functions (13 new):

• Level 1 (JTS): ST_AsText, ST_NPoints, ST_GeometryType, ST_NumGeometries, ST_Centroid
• Level 2 (JTS + Spheroid): ST_Distance, ST_Area, ST_Length
• Level 3 (S2): ST_MaxDistance, ST_ClosestPoint, ST_Contains, ST_Intersects, ST_Equals

Performance:

• ST_Distance uses S2ClosestEdgeQuery for true geometry-to-geometry distance (consistent with sedona-db)
• ShapeIndex cached in WKBGeography — 2-6x faster for repeated S2 operations
• Configurable spark.sedona.geography.eagerShapeIndex for predicate-heavy workloads
• JMH benchmark module with 4 benchmark classes (single-call, serializer comparison, GeoParquet scenario, batch processing)

Docs: API docs for all 13 new functions in docs/api/sql/geography/

Note: Geography-aware spatial join partitioning using S2 cells will be in a separate PR

How was this patch tested?

• 1032 unit tests pass in common module (28 new in WKBGeographyTest, 24 in FunctionTest)
• GeographyFunctionTest.scala — 34 Spark SQL integration tests covering constructors, structural functions, metrics, predicates, DataFrame API, and serialization round-trips
• JMH benchmarks verified across point, linestring, polygon (16/64/500 vertices) with GeoParquet scenario showing zero performance penalty vs S2-parse-from-WKB path

Did this PR include necessary documentation updates?

• Yes, I have updated the documentation.

[jiayuasu]

@zhangfengcdt Is this PR ready for review? It has lots of unnecessary content (e.g., the benchmark folder). Please also break this huge PR to several small pieces so we can review piece by piece.