docs: add pip installation path

[Sam123ben]

Summary

• make standard pip and uv first-class onboarding paths for the same immutable v0.53.0 wheel
• document the tesserix-adk distribution name versus the tesserix_adk import namespace
• update stale v0.51.0 dependency examples and explain reproducible pip requirements
• add a documentation contract that keeps both install paths visible

Validation

• red then green: test_readme_offers_pip_and_uv_install_paths
• clean Python 3.14 pip install and import from the public v0.53.0 wheel
• clean Python 3.14 uv add and import from the same wheel
• Ruff format/check and strict mypy
• documentation and release-workflow tests
• make docs-check