feat(config): добавлена поддержка устройства openvino в конфиге и auto-detect

- Зачем:
  - подготовка к OpenVINO бэкенду: config и utils должны знать о новом устройстве.
- Что:
  - config.py: openvino добавлен в _VALID_DEVICES и DEVICE_DEFAULTS (model=medium, compute_type=int8).
  - utils.py: detect_device() расширен цепочкой CUDA → OpenVINO → CPU; _is_openvino_available() проверяет архитектуру (x86_64/AMD64) и наличие openvino_genai.
  - cli.py: --device help text обновлён (auto|cpu|cuda|openvino).
  - добавлены тесты: config с openvino device, device defaults, auto-detect приоритет.
- Проверка:
  - uv run pytest -v — 103 passed.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

tests/test_config.py

@@ -128,3 +128,18 @@ def test_apply_device_defaults_config_overrides():
     result = apply_device_defaults(defaults, "cuda", cli, config)
     assert result["model"] == "small"
     assert result["compute_type"] == "int8"
+
+
+def test_load_config_openvino_device(tmp_path):
+    config = tmp_path / "config.toml"
+    config.write_text('device = "openvino"\n')
+    result = load_config(config)
+    assert result == {"device": "openvino"}
+
+
+def test_apply_device_defaults_openvino():
+    defaults = {"model": "medium", "language": "ru", "device": "auto", "compute_type": "float32"}
+    cli = {"model": None, "language": None, "device": None, "compute_type": None}
+    result = apply_device_defaults(defaults, "openvino", cli, {})
+    assert result["model"] == "medium"
+    assert result["compute_type"] == "int8"

tests/test_utils.py

@@ -58,6 +58,34 @@ def test_build_output_path_custom():
 def test_detect_device_explicit():
     assert detect_device("cpu") == "cpu"
     assert detect_device("cuda") == "cuda"
+    assert detect_device("openvino") == "openvino"
+
+
+def test_detect_device_auto_openvino():
+    """Нет nvidia-smi, есть openvino_genai, x86_64 → openvino."""
+    with (
+        patch("local_transcriber.utils.shutil.which", return_value=None),
+        patch("local_transcriber.utils._is_openvino_available", return_value=True),
+    ):
+        assert detect_device("auto") == "openvino"
+
+
+def test_detect_device_cuda_over_openvino():
+    """nvidia-smi доступен и openvino тоже → cuda побеждает."""
+    with (
+        patch("local_transcriber.utils.shutil.which", return_value="/usr/bin/nvidia-smi"),
+        patch("local_transcriber.utils._is_openvino_available", return_value=True),
+    ):
+        assert detect_device("auto") == "cuda"
+
+
+def test_detect_device_auto_cpu_fallback():
+    """Ни nvidia-smi, ни openvino → cpu."""
+    with (
+        patch("local_transcriber.utils.shutil.which", return_value=None),
+        patch("local_transcriber.utils._is_openvino_available", return_value=False),
+    ):
+        assert detect_device("auto") == "cpu"
 
 
 def test_get_gpu_name_no_nvidia_smi():