[feat] expose system controls and verify remote unlock completion

apps/desktop/src/platform/windows/screen_lock.cpp

@@ -5,6 +5,7 @@
  */
 
 #include "screen_lock.h"
+#include "service/interactive_desktop.h"
 
 #include <windows.h>
 
@@ -12,6 +13,13 @@
 
 namespace crossdesk {
 
+ScreenLockState QueryScreenLock() {
+  std::string reason;
+  if (IsCurrentSessionUnlocked(&reason)) return ScreenLockState::unlocked;
+  return reason.rfind("session_not_unlocked", 0) == 0 ? ScreenLockState::locked
+                                                     : ScreenLockState::unknown;
+}
+
 bool LockScreen() {
   if (LockWorkStation()) return true;
   LOG_WARN("LockWorkStation failed: {}", GetLastError());