refactor: convert hotkey module to package with evdev backend

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

whisper_local/hotkey/__init__.py

@@ -0,0 +1,24 @@
+"""Hotkey-Listener — plattformspezifische Backends hinter gemeinsamem Interface."""
+
+import sys
+from typing import Callable, Coroutine, Protocol, runtime_checkable
+
+AsyncCallback = Callable[[], Coroutine]
+
+
+@runtime_checkable
+class HotkeyListener(Protocol):
+    on_press: AsyncCallback | None
+    on_release: AsyncCallback | None
+
+    async def listen(self) -> None: ...
+
+
+def create_listener(key_name: str = "KEY_F12") -> HotkeyListener:
+    """Erstellt den plattformspezifischen HotkeyListener."""
+    if sys.platform == "linux":
+        from whisper_local.hotkey._evdev import EvdevHotkeyListener
+        return EvdevHotkeyListener(key_name)
+    else:
+        from whisper_local.hotkey._pynput import PynputHotkeyListener
+        return PynputHotkeyListener(key_name)