Add release-to-pypi-uv composite action

[leynos]

Summary

• add Release to PyPI (uv) composite action with scripted helpers
• document the action and capture scripting guidance in docs
• register the action in the root README

Testing

• UV_CACHE_DIR=/home/leynos/Projects/shared-actions/.cache/uv make test

Summary by Sourcery

Introduce a new composite action ‘release-to-pypi-uv’ to streamline release workflows with uv, bolster error handling and retries in existing actions, integrate cmd-mox for more robust command‐doubles testing, enforce lint/formatting in CI, and enrich documentation and tests across the repository

New Features:

• Add release-to-pypi-uv composite GitHub Action with step scripts for tag resolution, manual confirmation, GitHub release validation, TOML version checking, publishing, and summary writing
• Extend setup-windows-gnu action with configurable download retry logic and optional aarch64 compiler requirement

Enhancements:

• Refactor rust-build-release action to centralize runtime probing, support custom PROBE_TIMEOUT, and improve platform target detection
• Revamp generate-coverage run_rust logic to handle missing streams, errors, and ensure stream cleanup
• Integrate cmd-mox into rust-build-release and utils tests with new echo recorder fixture
• Update Makefile and CI workflows to include ruff lint/format checks, bunx action-validator, and Bun setup

Build:

• Add cmd-mox to dev dependencies in pyproject.toml

CI:

• Update workflows to install and configure Bun, run formatting and lint checks before testing

Documentation:

• Add release-to-pypi-uv action documentation and update root README
• Add cmd-mox usage guide and update scripting-standards for Cyclopts adoption

Tests:

• Add extensive unit and integration tests for the new release-to-pypi-uv scripts and action metadata
• Enhance existing rust-build-release tests with cmd-mox for cross‐version, container runtime and timeout scenarios