Formatters like pyproject-fmt and ruff format should run automatically when added to a project via use, so the codebase is immediately formatted to the configured style.

Changes

• Tool.apply() base method — No-op by default on the Tool Protocol class. Formatters override to invoke their CLI.
• PyprojectFmtTool.apply() — Runs uv run pyproject-fmt pyproject.toml with tick_print message. Guards on uv backend; suppresses subprocess errors (tool may not yet be installed in frozen mode).
• RuffTool.apply() — Runs uv run ruff format (not linter auto-fixes). Additionally guards on is_formatter_used().
• use_pyproject_fmt() / use_ruff() — Call tool.apply() after add_configs(), before print_how_to_use().
• Tests — Updated 6 existing output assertions, added 5 new unit tests covering both backends and formatter detection states. 100% coverage on new code.
• Docs — Updated README and detailed-example to reflect the new ✔ Running the Ruff formatter. / ✔ Running pyproject-fmt on 'pyproject.toml'. output lines.

# Pattern for formatter tools:
@override
def apply(self) -> None:
    if get_backend() is not BackendEnum.uv:
        return
    tick_print("Running the Ruff formatter.")
    with contextlib.suppress(UVSubprocessFailedError):
        call_uv_subprocess(["run", "ruff", "format"], change_toml=False)