Centralizes tool "add then run" testing into a single parameterized test over ALL_TOOLS instead of scattered per-tool tests.

Changes

• New TestUseTool.test_runs — parameterized over ALL_TOOLS, calls use_tool(tool) then runs tool.raw_cmd() via call_uv_subprocess on a fresh uv project
  • Tools without raw_cmd() (Coverage.py, MkDocs, pyproject.toml, requirements.txt, Ruff) skip via NoDefaultToolCommand
  • Pytest gets a placeholder test file to avoid exit code 5
• Removed TestCodespell.TestAdd.test_runs — now redundant with the parameterized test
• UI-level test_runs methods in test_tool.py kept (different test layer — CLI interface)

@pytest.mark.parametrize("tool", ALL_TOOLS, ids=lambda t: t.name)
@pytest.mark.usefixtures("_vary_network_conn")
def test_runs(self, tool: SupportedToolType, uv_env_dir: Path):
    with change_cwd(uv_env_dir), files_manager():
        use_tool(tool)
        try:
            cmd = tool.raw_cmd()
        except NoDefaultToolCommand:
            pytest.skip(f"{tool.name} has no default command")
        if isinstance(tool, PytestTool):
            (uv_env_dir / "tests" / "test_placeholder.py").write_text(
                "def test_placeholder(): pass\n"
            )
        call_uv_subprocess(["run", *shlex.split(cmd)], change_toml=False)

Also includes a pre-existing docs/functions.txt / AGENTS.md sync fix picked up by prek.