feat(media): SmtcController Skeleton mit circuit-breaker

Circuit-breaker-Pattern: Nach erstem Fehler beim SMTC-Manager-Zugriff
bleibt _broken=true und verhindert alle weiteren Zugriff-Versuche.
Logs Warnung einmalig und cleart _paused.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

tests/test_media_smtc.py

@@ -0,0 +1,75 @@
+"""Tests für SmtcController (Windows/SMTC)."""
+
+import sys
+from unittest.mock import AsyncMock, MagicMock
+
+import pytest
+
+pytestmark = pytest.mark.skipif(
+    sys.platform != "win32", reason="SMTC is Windows-only"
+)
+
+from winrt.windows.media.control import (
+    GlobalSystemMediaTransportControlsSessionPlaybackStatus as Status,
+)
+
+PLAYING = Status.PLAYING
+PAUSED = Status.PAUSED
+
+
+def _make_session(aumid: str, status) -> MagicMock:
+    """Erzeugt eine gemockte SMTC-Session mit gegebenem PlaybackStatus."""
+    session = MagicMock()
+    session.source_app_user_model_id = aumid
+    info = MagicMock()
+    info.playback_status = status
+    session.get_playback_info = MagicMock(return_value=info)
+    session.try_pause_async = AsyncMock()
+    session.try_play_async = AsyncMock()
+    return session
+
+
+def _make_manager(sessions: list) -> MagicMock:
+    """Erzeugt einen gemockten SMTC-Manager mit gegebenen Sessions."""
+    manager = MagicMock()
+    manager.get_sessions = MagicMock(return_value=sessions)
+    return manager
+
+
+@pytest.mark.asyncio
+async def test_pause_is_noop_when_smtc_unreachable(monkeypatch, caplog):
+    from whisper_local.media._smtc import SmtcController
+
+    controller = SmtcController()
+    monkeypatch.setattr(
+        controller,
+        "_ensure_manager",
+        AsyncMock(side_effect=RuntimeError("kein SMTC")),
+    )
+
+    with caplog.at_level("WARNING"):
+        await controller.pause()
+
+    assert controller._paused == []
+    assert any("SMTC" in r.message or "smtc" in r.message.lower() for r in caplog.records)
+
+
+@pytest.mark.asyncio
+async def test_pause_skips_reconnect_after_smtc_failure(monkeypatch):
+    from whisper_local.media._smtc import SmtcController
+
+    call_count = 0
+
+    async def failing_ensure():
+        nonlocal call_count
+        call_count += 1
+        raise RuntimeError("kein SMTC")
+
+    controller = SmtcController()
+    monkeypatch.setattr(controller, "_ensure_manager", failing_ensure)
+
+    await controller.pause()
+    await controller.pause()
+    await controller.pause()
+
+    assert call_count == 1