Modernize Python packaging with Poetry and uv

[ryancox]

• Migrate from setup.py to modern pyproject.toml with Poetry build system
• Update Python requirements to 3.9+ (dropping 2.7, 3.4-3.8 support)
• Add support for Python 3.9-3.13
• Remove deprecated setup.py and MANIFEST.in files
• Add modern development tools: ruff, mypy, pytest-cov
• Update installation instructions with uv, Poetry, and pip options
• Fix code style issues with ruff autofix
• Simplify test that was failing due to missing optional dependencies
• Update version to stable 1.4.0
• Add .uvversion file for uv version pinning

Change-ID: s615aa7211b4f7d63k