Add USBCANFD transport and visualize 0x391 door feedback

include/can_bus.hpp

@@ -0,0 +1,26 @@
+#pragma once
+#include "can_types.hpp"
+#include <memory>
+
+namespace cms {
+// One lifecycle per instance; only one owner per device index in a process.
+// start() must run after StopSignals so the receiver inherits its signal mask.
+// Missing hardware is reported by snapshot(), and does not stop inference.
+class CanBus {
+public:
+    explicit CanBus(CanConfig config);
+    ~CanBus();
+    CanBus(CanBus const&)=delete;
+    CanBus& operator=(CanBus const&)=delete;
+    void start();
+    void requestStop() noexcept;
+    void join() noexcept;
+    CanSnapshot snapshot() const;
+    // Thread-safe on-demand data-frame send; invalid frames throw, SDK failure
+    // returns false. Never generates periodic or inference-triggered messages.
+    bool send(CanFrame const& frame);
+private:
+    struct Impl;
+    std::unique_ptr<Impl> impl_;
+};
+}