Feature: Exclude human Web viewing from MCP remote control sessions

Complete the bidirectional mutual exclusion between MCP remote control
and human Web viewing (§8.2). Direction 1 (remote_open rejected while a
human session holds the screen sub-connection) already existed; this adds
direction 2: a human Web viewer is now rejected while an MCP session owns
the device.

Add a m_McpTriggeredDevices marker (mirroring m_MfcTriggeredDevices) that
is set when an MCP session is created (BeginScreenCtrlOpen) and cleared at
every session-erasure site (CloseScreenCtrlSession, SweepIdleScreenCtrl,
OnScreenControlClosed, EndScreenCtrlAction), so the marker cannot go stale
and permanently block humans. HandleConnect checks IsMcpTriggered before
mutating client state or starting the remote desktop.

Co-Authored-By: deepseek-v4-pro

server/2015Remote/WebService.cpp

@@ -643,6 +643,15 @@ void CWebService::HandleConnect(void* ws_ptr, const std::string& token, uint64_t
         }
     }
 
+    // Bidirectional mutex (direction 2, §8.2): reject human Web viewing while an MCP
+    // remote control session owns this host's screen sub-connection (SetMcpTriggered on
+    // remote_open, cleared on session teardown), so AI input cannot be injected into a
+    // picture a human is watching/controlling.
+    if (IsMcpTriggered(device_id)) {
+        SendText(ws_ptr, BuildJsonResponse("connect_result", false, "Device busy: remote control session active"));
+        return;
+    }
+
     // Check max clients per device
     int current_count = GetWebClientCount(device_id);
     if (current_count >= m_nMaxClientsPerDevice) {
@@ -2150,6 +2159,21 @@ void CWebService::ClearMfcTriggered(uint64_t device_id) {
     m_MfcTriggeredDevices.erase(device_id);
 }
 
+void CWebService::SetMcpTriggered(uint64_t device_id) {
+    std::lock_guard<std::mutex> lock(m_McpTriggeredMutex);
+    m_McpTriggeredDevices.insert(device_id);
+}
+
+bool CWebService::IsMcpTriggered(uint64_t device_id) {
+    std::lock_guard<std::mutex> lock(m_McpTriggeredMutex);
+    return m_McpTriggeredDevices.find(device_id) != m_McpTriggeredDevices.end();
+}
+
+void CWebService::ClearMcpTriggered(uint64_t device_id) {
+    std::lock_guard<std::mutex> lock(m_McpTriggeredMutex);
+    m_McpTriggeredDevices.erase(device_id);
+}
+
 bool CWebService::HasActiveSession(uint64_t device_id) {
     std::lock_guard<std::mutex> lock(m_ScreenContextsMutex);
     return m_ScreenContexts.find(device_id) != m_ScreenContexts.end();