Keep vanetza-idf in obu-firmware, so a plain clone builds the firmware

obu-firmware builds against the vanetza-idf C-ITS library, which until now
came from the colleague's microbu-esp32c5 tree beside the repository and was
not tracked here, so a clone of this repository could not build the firmware
it ships. The library alone is now part of obu-firmware, as
obu-firmware/external/vanetza-idf: their external/vanetza-idf at commit
cf4b99f, unchanged (9775 files; see its PROVENANCE.md). CMake takes it from
there by default; -DVANETZA_IDF_DIR still points the build elsewhere.

The rest of the colleague's tree (their own VAM firmware, PKI tooling,
station-link Python tools, the V2X2MAP bridge) stays out of this repository
and gitignored; nothing is pushed to their repository. NOTES.md, docs/06,
TODO.md and the pcap verifier's usage line point at the new location.

obu-firmware/external/vanetza-idf/tools/socktap/cam_application.hpp

@@ -0,0 +1,32 @@
+#ifndef CAM_APPLICATION_HPP_EUIC2VFR
+#define CAM_APPLICATION_HPP_EUIC2VFR
+
+#include "application.hpp"
+#include <vanetza/common/clock.hpp>
+#include <vanetza/common/position_provider.hpp>
+#include <vanetza/common/runtime.hpp>
+
+class CamApplication : public Application
+{
+public:
+    CamApplication(vanetza::PositionProvider& positioning, vanetza::Runtime& rt);
+    PortType port() override;
+    void indicate(const DataIndication&, UpPacketPtr) override;
+    void set_interval(vanetza::Clock::duration);
+    void set_station_id(std::uint32_t station_id);
+    void print_received_message(bool flag);
+    void print_generated_message(bool flag);
+
+private:
+    void schedule_timer();
+    void on_timer(vanetza::Clock::time_point);
+
+    vanetza::PositionProvider& positioning_;
+    vanetza::Runtime& runtime_;
+    vanetza::Clock::duration cam_interval_;
+    std::uint32_t station_id_ = 1;
+    bool print_rx_msg_ = false;
+    bool print_tx_msg_ = false;
+};
+
+#endif /* CAM_APPLICATION_HPP_EUIC2VFR */