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/application.hpp

@@ -0,0 +1,41 @@
+#ifndef APPLICATION_HPP_PSIGPUTG
+#define APPLICATION_HPP_PSIGPUTG
+
+#include <vanetza/btp/data_interface.hpp>
+#include <vanetza/btp/data_indication.hpp>
+#include <vanetza/btp/data_request.hpp>
+#include <vanetza/btp/port_dispatcher.hpp>
+#include <vanetza/geonet/data_confirm.hpp>
+#include <vanetza/geonet/router.hpp>
+
+class Application : public vanetza::btp::IndicationInterface
+{
+public:
+    using DataConfirm = vanetza::geonet::DataConfirm;
+    using DataIndication = vanetza::btp::DataIndication;
+    using DataRequest = vanetza::btp::DataRequestGeoNetParams;
+    using DownPacketPtr = vanetza::geonet::Router::DownPacketPtr;
+    using PortType = vanetza::btp::port_type;
+    using PromiscuousHook = vanetza::btp::PortDispatcher::PromiscuousHook;
+    using UpPacketPtr = vanetza::geonet::Router::UpPacketPtr;
+
+    Application() = default;
+    Application(const Application&) = delete;
+    Application& operator=(const Application&) = delete;
+    virtual ~Application() = default;
+
+    virtual PortType port() = 0;
+    virtual PromiscuousHook* promiscuous_hook();
+
+protected:
+    DataConfirm request(const DataRequest&, DownPacketPtr);
+
+private:
+    friend class RouterContext;
+    vanetza::geonet::GbcDataRequest request_gbc(const DataRequest&);
+    vanetza::geonet::ShbDataRequest request_shb(const DataRequest&);
+    vanetza::geonet::Router* router_;
+};
+
+#endif /* APPLICATION_HPP_PSIGPUTG */
+