[nemith]

Adds Python packages and distribution workflows for the NVUE schema library and CLI. nvueschema provides generated Pydantic models; the cli and full extras install nvueschema-binary, which supplies the native command and Go-backed validation API. The binary-only package supports uv tool install without Pydantic or a Python launcher.

• Adds a uv workspace, pinned model generation, isolated wheel tests, and wheels for Linux/macOS on amd64 and arm64 plus Windows amd64.
• Uses release tags to version both packages and their dependency pins. Prerelease tag pushes publish to TestPyPI; GitHub releases publish to PyPI. Publishing requires Go API compatibility and package-manager checks.
• Builds standalone CLI release archives for Linux, macOS, and Windows on amd64 and arm64, with checksums.
• Adds the Homebrew formula/update workflow for nemith/homebrew-tap and a pinned Nix flake, with installation instructions in the README.

Validation:

• Go/schema CI passes unit tests and all 19 NVUE versions.
• Packaging CI passes Python 3.10/3.14 tests on all five wheel platforms, pip/uv CLI installs, six CLI archive builds, Go API compatibility, and Homebrew/Nix tests on Linux and macOS.
• TestPyPI publishing succeeds using Trusted Publishing for both packages at tag v0.1.0-alpha.1. Published version: 0.1.0a1. The tagged commit and this PR's consolidated head have identical Git trees (c4813aa083a81087720395452c1d5ba41c69eee0).
• Fresh installs from TestPyPI pass all 45 API/CLI tests and pip check; standalone uv tool install also works. The base install remains independent of the native backend (39 tests pass, 6 native checks skip).
• Ruff, actionlint, and whitespace checks pass.

Test packages: nvueschema and nvueschema-binary. This trial does not publish to production PyPI, create a GitHub release, or update the Homebrew formula.