Story: Decode WKT Point geometries #8

Goal

Add WKT decoding support for POINT geometries using the WKT decoding architecture.

The decoder must parse Point representations, preserve their coordinate dimension, and construct the corresponding immutable spatial object without implicit conversion or loss of spatial information.

Acceptance criteria

• POINT is decoded into the corresponding spatial object.
• XY, XYZ, XYM and XYZM coordinates are supported.
• POINT EMPTY is supported.
• Coordinate values and dimensions are preserved exactly as represented.
• Invalid Point representations are explicitly rejected.
• No unsupported coordinate or dimension is silently discarded or converted.
• Unit tests cover supported dimensions, EMPTY, and invalid representations.
• The standard test and quality suites pass.

Out of scope

• Other geometry types.
• EWKT and SRID-prefixed representations.
• Coordinate reprojection.
• Implicit coordinate dimension conversion.