feat: add shell install wizard

tests/test_install_script.py

@@ -0,0 +1,39 @@
+import shutil
+import subprocess
+from pathlib import Path
+
+import pytest
+
+REPO_ROOT = Path(__file__).resolve().parents[1]
+INSTALL_SCRIPT = REPO_ROOT / "scripts" / "install.sh"
+
+
+def test_shell_installer_help_does_not_require_python():
+    if not shutil.which("sh"):
+        pytest.skip("sh is not available on this platform")
+
+    result = subprocess.run(
+        ["sh", str(INSTALL_SCRIPT), "--help"],
+        check=True,
+        text=True,
+        capture_output=True,
+    )
+
+    assert "MINISHOP_INSTALL_REPO" in result.stdout
+    assert "dry-run" in result.stdout
+
+
+def test_shell_installer_is_the_only_install_entrypoint():
+    assert INSTALL_SCRIPT.exists()
+    assert not (REPO_ROOT / "scripts" / "install.py").exists()
+
+
+def test_shell_installer_downloads_raw_files_and_runs_import_in_container():
+    script = INSTALL_SCRIPT.read_text(encoding="utf-8")
+
+    assert script.startswith("#!/bin/sh")
+    assert "raw.githubusercontent.com" in script
+    assert "git clone" not in script
+    assert "backend python backend/scripts/import_legacy.py" in script
+    assert "--dry-run" in script
+    assert "Install new stack and run legacy migration" in script