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_config.py

@@ -137,9 +137,39 @@ def test_load_config_openvino_device(tmp_path):
     assert result == {"device": "openvino"}
 
 
+def test_load_config_openvino_gpu_device(tmp_path):
+    config = tmp_path / "config.toml"
+    config.write_text('device = "openvino-gpu"\n')
+    result = load_config(config)
+    assert result == {"device": "openvino-gpu"}
+
+
+def test_load_config_openvino_cpu_device(tmp_path):
+    config = tmp_path / "config.toml"
+    config.write_text('device = "openvino-cpu"\n')
+    result = load_config(config)
+    assert result == {"device": "openvino-cpu"}
+
+
 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"
+
+
+def test_apply_device_defaults_openvino_gpu():
+    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-gpu", cli, {})
+    assert result["model"] == "medium"
+    assert result["compute_type"] == "int8"
+
+
+def test_apply_device_defaults_openvino_cpu():
+    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-cpu", cli, {})
+    assert result["model"] == "medium"
+    assert result["compute_type"] == "int8"