Universal Decompositional Semantics (v2.0) and Decomp (v0.3.1)

Fixes missing semantics module in PyPI distribution

The PyPI package was missing the entire semantics subpackage due to incorrect
package discovery configuration in pyproject.toml. This made the package
completely unusable when installed from PyPI.

Changes:

• Fixed package configuration to use setuptools automatic package discovery
• Added __version__ attribute to the package for version introspection
• Updated package data pattern to include all nested data files

This is a critical bug fix that restores core functionality for PyPI users.