fix: suppress key-repeat events in pynput hotkey listener

Holding the hotkey caused dozens of on_press callbacks due to OS key-repeat.
Added a _pressed guard flag so only the first press and actual release fire.

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

whisper_local/hotkey/_pynput.py

@@ -36,6 +36,7 @@ class PynputHotkeyListener:
         self.on_press: AsyncCallback | None = None
         self.on_release: AsyncCallback | None = None
         self._loop: asyncio.AbstractEventLoop | None = None
+        self._pressed = False
 
     async def _handle_key_event(self, key_down: bool) -> None:
         """Ruft den passenden Callback auf."""
@@ -54,12 +55,14 @@ class PynputHotkeyListener:
         )
 
     def _on_press(self, key) -> None:
-        if key == self._target_key:
+        if key == self._target_key and not self._pressed:
+            self._pressed = True
             logger.debug("%s gedrückt", self.key_name)
             self._schedule_callback(key_down=True)
 
     def _on_release(self, key) -> None:
-        if key == self._target_key:
+        if key == self._target_key and self._pressed:
+            self._pressed = False
             logger.debug("%s losgelassen", self.key_name)
             self._schedule_callback(key_down=False)