feat(openvino): добавлена поддержка Intel GPU через OpenVINO

- Зачем:
  - OpenVINO backend хардкодил "CPU", хотя Intel Arc GPU доступен и даёт ~2x ускорение.
- Что:
  - новые device modes: --device openvino-gpu, openvino-cpu; openvino — авто-детект GPU/CPU.
  - detect_device() проверяет Intel GPU через OpenVINO Core API (с fail-safe).
  - OpenVINOBackend передаёт "GPU"/"CPU" в WhisperPipeline вместо хардкода "CPU".
  - подсказка "Совет: --model large-v3" при наличии GPU и модели не large-v3.
  - .gitattributes для нормализации line endings (eol=lf).
  - 150 тестов, включая GPU detection, routing, fallback, CLI device info.
  - README, docs/gpu.md, docs/PRD.md обновлены для Intel GPU.
- Проверка:
  - uv run pytest (150 passed).
  - uv run transcribe --device openvino-gpu file.mp4 на Intel Arc 140T GPU.

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

tests/test_backend_openvino.py

@@ -104,17 +104,70 @@ def test_ensure_model_available_downloads(mock_download, tmp_path):
 # === create_model ===
 
 
-def test_create_model():
+def test_create_model_cpu():
     mock_ov = MagicMock()
     mock_pipeline = MagicMock()
     mock_ov.WhisperPipeline.return_value = mock_pipeline
 
-    backend = OpenVINOBackend()
+    backend = OpenVINOBackend(ov_device="openvino-cpu")
     with patch.dict("sys.modules", {"openvino_genai": mock_ov}):
-        model = backend.create_model("/path/to/model", "openvino", "int8")
+        model = backend.create_model("/path/to/model", "openvino-cpu", "int8")
 
     mock_ov.WhisperPipeline.assert_called_once_with("/path/to/model", "CPU")
     assert model is mock_pipeline
+    assert backend.actual_ov_device == "CPU"
+
+
+def test_create_model_gpu():
+    mock_ov = MagicMock()
+    mock_pipeline = MagicMock()
+    mock_ov.WhisperPipeline.return_value = mock_pipeline
+
+    backend = OpenVINOBackend(ov_device="openvino-gpu")
+    with patch.dict("sys.modules", {"openvino_genai": mock_ov}):
+        model = backend.create_model("/path/to/model", "openvino-gpu", "fp16")
+
+    mock_ov.WhisperPipeline.assert_called_once_with("/path/to/model", "GPU")
+    assert model is mock_pipeline
+    assert backend.actual_ov_device == "GPU"
+
+
+def test_create_model_openvino_auto_detects_gpu():
+    """ov_device='openvino' + GPU доступен → WhisperPipeline получает 'GPU'."""
+    mock_ov = MagicMock()
+    mock_pipeline = MagicMock()
+    mock_ov.WhisperPipeline.return_value = mock_pipeline
+
+    mock_core = MagicMock()
+    mock_core.return_value.available_devices = ["CPU", "GPU"]
+
+    backend = OpenVINOBackend(ov_device="openvino")
+    with (
+        patch.dict("sys.modules", {"openvino_genai": mock_ov, "openvino": MagicMock(Core=mock_core)}),
+    ):
+        model = backend.create_model("/path/to/model", "openvino", "int8")
+
+    mock_ov.WhisperPipeline.assert_called_once_with("/path/to/model", "GPU")
+    assert backend.actual_ov_device == "GPU"
+
+
+def test_create_model_openvino_auto_falls_back_to_cpu():
+    """ov_device='openvino' + нет GPU → WhisperPipeline получает 'CPU'."""
+    mock_ov = MagicMock()
+    mock_pipeline = MagicMock()
+    mock_ov.WhisperPipeline.return_value = mock_pipeline
+
+    mock_core = MagicMock()
+    mock_core.return_value.available_devices = ["CPU"]
+
+    backend = OpenVINOBackend(ov_device="openvino")
+    with (
+        patch.dict("sys.modules", {"openvino_genai": mock_ov, "openvino": MagicMock(Core=mock_core)}),
+    ):
+        model = backend.create_model("/path/to/model", "openvino", "int8")
+
+    mock_ov.WhisperPipeline.assert_called_once_with("/path/to/model", "CPU")
+    assert backend.actual_ov_device == "CPU"
 
 
 # === transcribe ===