Align published package version with release tag 0.5.1

[Copilot]

pip reported pycddp 0.1.0 because the package metadata and embedded version constants were still pinned to the initial release. This updates the version sources so the published Python package reports 0.5.1, matching the current release line.

• Version metadata

  • Bump the Python package version in pyproject.toml to 0.5.1
  • Update the runtime-exported pycddp.__version__ constant to 0.5.1
  • Sync the top-level CMake project version to 0.5.1

• Consistency across release surfaces

  • Keep Python packaging metadata, import-time version reporting, and CMake project metadata aligned to avoid version drift across builds and published artifacts

[project]
name = "pycddp"
version = "0.5.1"