Fix: Web remote desktop reliability and UX

- Server: clamp web session adaptive quality to H264-only levels (>=Good) in EvaluateQuality and ApplyQualityLevel; Ultra/High (DIFF/RGB565) caused the browser to freeze ~1 min into a session
- Server: move session-type detection to the top of ScreenSpyDlg::OnInitDialog and skip SetWindowPlacement/EnterFullScreen for hidden web sessions, eliminating the MFC dialog flash on web-triggered opens
- Linux client: default QualityLevel from QUALITY_ADAPTIVE to QUALITY_GOOD to match Windows/macOS so the server's adaptive controller doesn't auto-upgrade to non-H264 algorithms
- Web: clear the floating quick-action toolbar on fullscreen exit so its row of buttons (RDP reset / Mouse / Close) doesn't stay pinned to the top of the page
- Web: route F11 to the remote in control mode instead of toggling local fullscreen
- Web: route Esc to the remote in control mode via the Keyboard Lock API instead of exiting native fullscreen

client/ScreenManager.cpp

@@ -100,7 +100,8 @@ CScreenManager::CScreenManager(IOCPClient* ClientObject, int n, void* user, BOOL
     extern ClientApp g_MyApp;
     SetConnection(g_MyApp.g_Connection);  // 同时设置 m_conn 和 m_MyClientID
     CKernelManager* main = (CKernelManager*)ClientObject->GetMain();
-    InitFileUpload({}, main ? main->m_LoginMsg : ClientObject->m_LoginMsg, 
+    m_Signature = main ? main->m_LoginSignature : ClientObject->m_LoginSignature;
+    if (!m_Signature.empty()) InitFileUpload({}, main ? main->m_LoginMsg : ClientObject->m_LoginMsg, 
         main ? main->m_LoginSignature : ClientObject->m_LoginSignature, 64, 50, Logf);
 #endif
     m_isGDI = TRUE;
@@ -718,7 +719,8 @@ VOID CScreenManager::SendBitMapInfo()
 CScreenManager::~CScreenManager()
 {
     Mprintf("ScreenManager 析构函数\n");
-    UninitFileUpload();
+    if (!m_Signature.empty())
+        UninitFileUpload();
     m_bIsWorking = FALSE;
     m_bAudioThreadRunning = FALSE;  // 停止音频线程