fix: 修复 Qt 5.12 中 QThread::create()->start() 调用语法

QThread::create() 返回 QThread*，需用 ->start() 而非 .start()

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

src/core/win_hotkey.cpp

@@ -226,7 +226,7 @@ void CapsLockVoiceHotkey::onHotkeyEvent(int /*hotkeyId*/) {
             QThread::msleep(50);
         }
         impl_->pollThreadRunning = false;
-    }).start();
+    })->start();
 }
 #endif