Release 0.6.0

Features

• Add cargo binstall support for pre-built binary installation
• Replace custom update checker with moz-cli-version-check (shared cache with other Mozilla CLI tools)
• update subcommand now tries cargo binstall first, falling back to cargo install
• Add CI workflow for tests, formatting, clippy checks, and cross-platform release builds

Fixes

• init: skip pre-commit setup and "Next steps" message when repository is already initialized