fix: snapmakerprinteragent use moonraker's lifecycle-owned command worker

src/slic3r/Utils/MoonrakerPrinterAgent.hpp

@@ -136,6 +136,10 @@ protected:
 
     virtual void on_status_loop_tick(const std::string& dev_id) {}
 
+    // Queue work that may use agent state. The command worker is joined during
+    // destruction, so queued commands cannot outlive the agent.
+    void enqueue_command(std::function<void()> fn);
+
 private:
     int handle_request(const std::string& dev_id, const std::string& json_str);
     int send_version_info(const std::string& dev_id);
@@ -254,7 +258,6 @@ private:
     std::thread            connect_thread;
     mutable std::recursive_mutex connect_mutex;
 
-    void enqueue_command(std::function<void()> fn);
     void run_command_worker();
     std::thread cmd_thread;
     std::deque<std::function<void()>> cmd_queue;

src/slic3r/Utils/SnapmakerPrinterAgent.cpp

@@ -82,10 +82,10 @@ SnapmakerPrinterAgent::SnapmakerPrinterAgent(std::string log_dir) : MoonrakerPri
 
 void SnapmakerPrinterAgent::start_camera_monitor()
 {
-    std::thread([this] {
+    enqueue_command([this] {
         send_ws_rpc("camera.start_monitor",
                     {{"domain", "lan"}, {"interval", 0}, {"expect_pw", false}});
-    }).detach();
+    });
     m_camera_last_fire_ms.store(now_ms());
 }