Release v0.2.5 and prepare the first PyPI distribution

[initial-d]

Summary

• bump package, runtime, citation, and Zenodo metadata to 0.2.5
• add a PyPI-specific long description with absolute project links
• make pip install mlquant the primary user installation path
• add v0.2.5 changelog and release notes
• modernize SPDX license metadata for current build tooling

Distribution verification

• built mlquant-0.2.5-py3-none-any.whl and mlquant-0.2.5.tar.gz in an isolated build environment
• both artifacts passed twine check --strict
• wheel contains the packaged demo config, LICENSE, and NOTICE
• sdist contains the PyPI README and packaged config
• installed the wheel with all declared dependencies in a fresh Python 3.9 environment
• from a directory outside the repository, confirmed version 0.2.5, CLI help, and the complete mlquant demo pipeline through report generation

Research boundary

The bundled demo uses deterministic synthetic data and verifies engineering behavior only. It is not investment advice or a live-performance claim.

After merge, this commit will be tagged v0.2.5, attached to a GitHub Release with both artifacts, and uploaded to PyPI as the first mlquant distribution.