feat: extract reusable dev/CI tools from GRM into devx package

Port core modules (config, exceptions, i18n, api_clients, gitea_cli),
14 CI scripts, 6 dev tools, 5 molecule tools, CLI entry point, workflows,
Makefile, tests (784 tests, 100% coverage), and documentation from GRM.

The devx package is published to the Gitea PyPI registry and consumed
by GRM, infra, and other oblachno-oss projects as a pip dependency.

Generated with [Devin](https://devin.ai)

Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

tests/unit/test_install_checkmake.py

@@ -0,0 +1,94 @@
+from __future__ import annotations
+
+import platform
+from pathlib import Path
+from unittest.mock import patch
+
+import pytest
+from click import ClickException
+
+import devx.tools.install_checkmake as install_checkmake
+
+
+class TestArch:
+    def test_amd64(self) -> None:
+        with patch.object(platform, "machine", return_value="x86_64"):
+            assert install_checkmake._arch() == "amd64"
+
+    def test_arm64(self) -> None:
+        with patch.object(platform, "machine", return_value="aarch64"):
+            assert install_checkmake._arch() == "arm64"
+
+    def test_unsupported(self) -> None:
+        with patch.object(platform, "machine", return_value="riscv64"):
+            with pytest.raises(ClickException):
+                install_checkmake._arch()
+
+
+class TestInstallWithGo:
+    def test_no_go(self) -> None:
+        with patch("shutil.which", return_value=None):
+            assert install_checkmake._install_with_go() is False
+
+    def test_with_go(self) -> None:
+        with patch("shutil.which", return_value="/usr/bin/go"):
+            with patch("subprocess.run") as mock_run:
+                assert install_checkmake._install_with_go() is True
+                mock_run.assert_called_once_with(
+                    [
+                        "/usr/bin/go",
+                        "install",
+                        "github.com/checkmake/checkmake/cmd/checkmake@latest",
+                    ],
+                    check=True,
+                )
+
+
+class TestDownloadBinary:
+    def test_download(self, tmp_path: Path) -> None:
+        target = tmp_path / "checkmake"
+
+        def _write_file(url: str, path: str) -> tuple[str, None]:
+            Path(path).write_bytes(b"binary")
+            return path, None
+
+        with patch.object(install_checkmake, "TARGET_PATH", target):
+            with patch.object(platform, "machine", return_value="x86_64"):
+                with patch("urllib.request.urlretrieve", side_effect=_write_file) as mock_retrieve:
+                    install_checkmake._download_binary()
+        mock_retrieve.assert_called_once()
+        assert target.exists()
+        assert target.stat().st_mode & 0o111
+
+
+class TestMain:
+    def test_already_installed(self) -> None:
+        with patch("shutil.which", return_value="/usr/bin/checkmake"):
+            install_checkmake.main()
+
+    def test_install_with_go(self) -> None:
+        with patch("shutil.which", side_effect=[None, "/usr/bin/go"]):
+            with patch("subprocess.run") as mock_run:
+                install_checkmake.main()
+                mock_run.assert_called_once_with(
+                    [
+                        "/usr/bin/go",
+                        "install",
+                        "github.com/checkmake/checkmake/cmd/checkmake@latest",
+                    ],
+                    check=True,
+                )
+
+    def test_download_when_no_go(self, tmp_path: Path) -> None:
+        target = tmp_path / "checkmake"
+
+        def _write_file(url: str, path: str) -> tuple[str, None]:
+            Path(path).write_bytes(b"binary")
+            return path, None
+
+        with patch.object(install_checkmake, "TARGET_PATH", target):
+            with patch("shutil.which", side_effect=[None, None]):
+                with patch.object(platform, "machine", return_value="x86_64"):
+                    with patch("urllib.request.urlretrieve", side_effect=_write_file) as mock_retrieve:
+                        install_checkmake.main()
+                        mock_retrieve.assert_called_once()