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/router_context.hpp

@@ -0,0 +1,50 @@
+#ifndef ROUTER_CONTEXT_HPP_KIPUYBY2
+#define ROUTER_CONTEXT_HPP_KIPUYBY2
+
+#include "dcc_passthrough.hpp"
+#include "link_layer.hpp"
+#include <vanetza/btp/port_dispatcher.hpp>
+#include <vanetza/common/position_provider.hpp>
+#include <vanetza/geonet/mib.hpp>
+#include <vanetza/geonet/router.hpp>
+#include <array>
+#include <list>
+#include <memory>
+
+class Application;
+class TimeTrigger;
+
+class RouterContext
+{
+public:
+    RouterContext(const vanetza::geonet::MIB&, TimeTrigger&, vanetza::PositionProvider&, vanetza::security::SecurityEntity*);
+    ~RouterContext();
+    void enable(Application*);
+    void disable(Application*);
+
+    /**
+     * Allow/disallow transmissions without GNSS position fix
+     *
+     * \param flag true if transmissions shall be dropped when no GNSS position fix is available
+     */
+    void require_position_fix(bool flag);
+
+    void set_link_layer(LinkLayer*);
+
+private:
+    void indicate(vanetza::CohesivePacket&& packet, const vanetza::EthernetHeader& hdr);
+    void log_packet_drop(vanetza::geonet::Router::PacketDropReason);
+    void update_position_vector();
+    void update_packet_flow(const vanetza::geonet::LongPositionVector&);
+
+    vanetza::geonet::MIB mib_;
+    vanetza::geonet::Router router_;
+    TimeTrigger& trigger_;
+    vanetza::PositionProvider& positioning_;
+    vanetza::btp::PortDispatcher dispatcher_;
+    std::unique_ptr<DccPassthrough> request_interface_;
+    std::list<Application*> applications_;
+    bool require_position_fix_ = false;
+};
+
+#endif /* ROUTER_CONTEXT_HPP_KIPUYBY2 */