Add GeoJsonReader.geometryFrom(string:data:) helpers that auto-detect whether a payload is GeoJSON, WKT (with or without an SRID prefix), or hex-encoded WKB/EWKB/TWKB, and decode it into a GeoJsonGeometry.
Also:
- Make WKBCoder's sourceProjection optional so the embedded SRID is auto-detected from EWKB payloads.
- Fix a division-by-zero crash in Data(hex:) for non-hex input.