refactor: convert hotkey module to package with evdev backend

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

tests/test_hotkey.py

@@ -1,14 +1,16 @@
 import asyncio
+import sys
 from unittest.mock import AsyncMock, MagicMock, patch
 
 import pytest
 
-from whisper_local.hotkey import HotkeyListener
+pytestmark = pytest.mark.skipif(sys.platform != "linux", reason="evdev only available on Linux")
 
 
 @pytest.fixture
 def listener():
-    return HotkeyListener(key_name="KEY_F12")
+    from whisper_local.hotkey._evdev import EvdevHotkeyListener
+    return EvdevHotkeyListener(key_name="KEY_F12")
 
 
 class TestHotkeyListener:
@@ -33,6 +35,5 @@ class TestHotkeyListener:
 
     @pytest.mark.asyncio
     async def test_no_callback_no_error(self, listener):
-        # Kein Callback gesetzt — soll nicht crashen
         await listener._handle_key_event(key_down=True)
         await listener._handle_key_event(key_down=False)