epic: st function coverage

This document outlines the ST functions implemented in the latest version of SedonaDB. Feel free to create PRs to add support for more ST functions!

The full list is from SedonaSpark: https://sedona.apache.org/latest/api/sql/Function/

Note that this list might not be up-to-date! Check https://sedona.apache.org/sedonadb/latest/reference/sql/ before implementing a function to make sure it hasn't been implemented yet (and let us know if it isn't up to date!)

## Constructor Functions

- [x] ST_GeogPoint (v0.2)
- [x] ST_GeogFromWKB (v0.2)
- [x] ST_GeogFromWKT (v0.2)
- [x] ST_GeomCollFromText (#205)
- [x] ST_GeomFromEWKB
- [x] ST_GeomFromEWKT
- [ ] ST_GeomFromGML
- [ ] ST_GeomFromGeoHash
- [ ] ST_GeomFromGeoJSON
- [ ] ST_GeomFromKML
- [x] ST_GeomFromText (alias for ST_GeomFromWKT) (v0.1)
- [x] ST_GeomFromWKB (v0.1)
- [x] ST_GeomFromWKT (v0.1)
- [x] ST_GeometryFromText (#200)
- [x] ST_LineFromText (#205)
- [ ] ST_LineFromWKB (#206)
- [x] ST_LineStringFromText (#205)
- [ ] ST_LinestringFromWKB (#206)
- [ ] ST_MakeEnvelope
- [x] ST_MLineFromText (#205)
- [x] ST_MPointFromText (#205)
- [x] ST_MPolyFromText (#205)
- [ ] ST_MakePoint
- [ ] ST_MakePointM
- [x] ST_Point (v0.1)
- [ ] ST_PointFromGeoHash
- [x] ST_PointFromText (#205)
- [x] ST_PointZ (v0.1)
- [x] ST_PointM (v0.1)
- [x] ST_PointZM (v0.1)
- [ ] ST_PointFromWKB (#206)
- [ ] ST_PolygonFromEnvelope
- [x] ST_PolygonFromText (#205)

## Geometry Functions

- [ ] GeometryType
- [ ] ST_3DDistance
- [ ] ST_AddMeasure
- [ ] ST_AddPoint
- [x] ST_Affine
- [ ] ST_Angle
- [x] ST_Area (v0.1)
- [ ] ST_AreaSpheroid
- [x] ST_AsBinary (v0.1)
- [x] ST_AsEWKB
- [x] ST_AsEWKT
- [x] ST_AsGeoJSON
- [ ] ST_AsGML
- [ ] ST_AsHEXEWKB
- [ ] ST_AsKML
- [x] ST_AsText (v0.1)
- [x] ST_Azimuth (v0.2)
- [ ] ST_BestSRID
- [ ] ST_BinaryDistanceBandColumn
- [x] ST_Boundary (v0.2)
- [ ] ST_BoundingDiagonal
- [x] ST_Buffer (v0.1)
- [ ] ST_BuildArea
- [x] ST_Centroid (v0.1)
- [x] ST_ClosestPoint (v0.2)
- [x] ST_Collect (v0.1)
- [ ] ST_CollectionExtract
- [ ] ST_ConcaveHull
- [x] ST_ConvexHull (v0.2)
- [ ] ST_CoordDim
- [ ] ST_CrossesDateLine
- [x] ST_CRS (v0.2)
- [ ] ST_DBSCAN
- [ ] ST_Degrees
- [ ] ST_DelaunayTriangles
- [x] ST_Difference (v0.1)
- [x] ST_Dimension (v0.1)
- [x] ST_Distance (v0.1)
- [ ] ST_DistanceSphere
- [ ] ST_DistanceSpheroid
- [x] ST_Dump (v0.2)
- [ ] ST_DumpPoints
- [x] ST_EndPoint (v0.2)
- [x] ST_Envelope (v0.1)
- [ ] ST_Expand
- [ ] ST_ExteriorRing
- [x] ST_FlipCoordinates (v0.1)
- [ ] ST_Force_2D
- [x] ST_Force2D
- [x] ST_Force3D
- [x] ST_Force3DM
- [x] ST_Force3DZ
- [x] ST_Force4D
- [ ] ST_ForceCollection
- [ ] ST_ForcePolygonCCW
- [ ] ST_ForcePolygonCW
- [ ] ST_ForceRHR
- [ ] ST_FrechetDistance (v0.1)
- [ ] ST_GeneratePoints
- [ ] ST_GeoHash
- [ ] ST_GeometricMedian
- [x] ST_GeometryN (v0.2)
- [x] ST_GeometryType (v0.1)
- [ ] ST_GLocal
- [ ] ST_H3CellDistance
- [ ] ST_H3CellIDs
- [ ] ST_H3KRing
- [ ] ST_H3ToGeom
- [x] ST_HasM (v0.1)
- [x] ST_HasZ (v0.1)
- [x] ST_HausdorffDistance
- [x] ST_InteriorRingN
- [ ] ST_InterpolatePoint
- [x] ST_Intersection (v0.1)
- [x] ST_IsClosed (v0.2)
- [x] ST_IsCollection
- [x] ST_IsEmpty (v0.1)
- [ ] ST_IsPolygonCCW
- [ ] ST_IsPolygonCW
- [x] ST_IsRing (v0.2)
- [x] ST_IsSimple (v0.2)
- [x] ST_IsValid (v0.2)
- [ ] ST_IsValidDetail
- [x] ST_IsValidReason (v0.2)
- [ ] ST_IsValidTrajectory
- [ ] ST_LabelPoint
- [x] ST_Length (v0.1)
- [ ] ST_Length2D
- [ ] ST_LengthSpheroid
- [ ] ST_LineFromMultiPoint
- [x] ST_LineInterpolatePoint (v0.2)
- [x] ST_LineLocatePoint (v0.2)
- [ ] ST_LineMerge
- [ ] ST_LineSegments
- [ ] ST_LineSubstring
- [ ] ST_LocalOutlierFactor
- [ ] ST_LocateAlong
- [ ] ST_LongestLine
- [x] ST_M (v0.1)
- [x] ST_MMax (v0.1)
- [x] ST_MMin (v0.1)
- [x] ST_MakeLine (v0.1)
- [ ] ST_MakePolygon
- [x] ST_MakeValid (v0.2)
- [ ] ST_MaximumInscribedCircle
- [x] ST_MaxDistance (v0.1)
- [x] ST_MinimumClearance (v0.2)
- [x] ST_MinimumClearanceLine (v0.2)
- [ ] ST_MinimumBoundingCircle
- [ ] ST_MinimumBoundingRadius
- [ ] ST_Multi
- [ ] ST_NDims
- [x] ST_Normalize
- [x] ST_NPoints (v0.2)
- [x] ST_NRings
- [x] ST_NumGeometries (v0.2)
- [ ] ST_NumInteriorRing
- [x] ST_NumInteriorRings
- [ ] ST_NumPoints
- [x] ST_Perimeter (v0.1)
- [ ] ST_Perimeter2D
- [x] ST_PointN (v0.2)
- [ ] ST_PointOnSurface
- [x] ST_Point (v0.1)
- [x] ST_Points (v0.2)
- [ ] ST_Polygon
- [x] ST_Polygonize (v0.2)
- [ ] ST_Project
- [ ] ST_ReducePrecision
- [ ] ST_RemovePoint
- [ ] ST_RemoveRepeatedPoints
- [x] ST_Reverse (v0.2)
- [ ] ST_Rotate
- [ ] ST_RotateX
- [ ] ST_RotateY
- [x] ST_SetCRS (v0.2)
- [ ] ST_S2CellIDs
- [ ] ST_S2ToGeom
- [x] ST_Scale
- [ ] ST_ScaleGeom
- [ ] ST_SetPoint
- [x] ST_SetSRID (v0.1)
- [ ] ST_ShiftLongitude
- [x] ST_Simplify (v0.2)
- [ ] ST_SimplifyPolygonHull
- [x] ST_SimplifyPreserveTopology (v0.2)
- [ ] ST_SimplifyVW
- [x] ST_Snap (v0.2)
- [ ] ST_Split
- [x] ST_SRID (v0.1)
- [x] ST_StartPoint (v0.2)
- [ ] ST_SubDivide
- [ ] ST_SubDivideExplode
- [x] ST_SymDifference (v0.1)
- [x] ST_Transform (v0.1)
- [x] ST_Translate (v0.2)
- [ ] ST_TriangulatePolygon
- [x] ST_UnaryUnion (v0.2)
- [x] ST_Union (v0.1)
- [ ] ST_VoronoiPolygons
- [ ] ST_WeightedDistanceBandColumn
- [x] ST_X (v0.1)
- [x] ST_XMax (v0.1)
- [x] ST_XMin (v0.1)
- [x] ST_Y (v0.1)
- [x] ST_YMax (v0.1)
- [x] ST_YMin (v0.1)
- [x] ST_Z (v0.1)
- [x] ST_ZMax (v0.1)
- [x] ST_ZMin (v0.1)
- [x] ST_Zmflag (v0.2)

## Predicate Functions

- [x] ST_Contains (v0.1)
- [x] ST_Covers (v0.1)
- [x] ST_CoveredBy (v0.1)
- [x] ST_Crosses (v0.2)
- [x] ST_Disjoint (v0.1)
- [x] ST_DWithin (v0.1)
- [x] ST_Equals (v0.1)
- [x] ST_Intersects (v0.1)
- [ ] ST_OrderingEquals
- [x] ST_Overlaps (v0.2)
- [x] ST_Relate
- [ ] ST_RelateMatch
- [x] ST_Touches (v0.1)
- [x] ST_Within (v0.1)

## Aggregate Functions

- [x] ST_Analyze_Agg (v0.1)
- [x] ST_Collect_Agg (v0.2)
- [x] ST_Envelope_Agg (v0.1)
- [x] ST_Intersection_Agg (v0.1)
- [x] ST_Polygonize_Agg (v0.2)
- [x] ST_Union_Agg (v0.1)

## Advanced Functions

- [x] ST_KNN (v0.1)

Compare the unchecked functions in this issue with the SedonaDB SQL reference, using the SedonaSpark function list as a broader checklist. Choose one function whose support is not already implemented, then inspect the existing Rust implementation patterns and related coverage before starting. Done means the selected ST function is supported, covered by appropriate tests, and marked complete here.

Written by the indexing model from the issue text.