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/vanetza/geonet/dcc_information_sharing.hpp

@@ -0,0 +1,90 @@
+#ifndef DCC_INFORMATION_SHARING_HPP_GZCSHZLD
+#define DCC_INFORMATION_SHARING_HPP_GZCSHZLD
+
+#include <vanetza/common/clock.hpp>
+#include <vanetza/common/hook.hpp>
+#include <vanetza/common/unit_interval.hpp>
+#include <vanetza/geonet/cbr_aggregator.hpp>
+#include <vanetza/geonet/dcc_field_generator.hpp>
+
+namespace vanetza
+{
+
+class Runtime;
+
+namespace geonet
+{
+
+class LocationTable;
+
+/**
+ * DccInformationSharing realises the DCC_NET behaviour for ITS-G5, originally specified by
+ * TS 102 636-4-2 V1.1.1 and carried forward by TS 103 836-4-2 V2.1.1 clauses 5.3-5.4
+ * (Release 2; the CBR_G algorithm and trigger cadence implemented here match the current
+ * text step-for-step). CBR_target corresponds to the Release-2 protocol constant
+ * itsGNCBRTarget (TS 103 836-4-2 V2.1.1 Annex A: 0,62), which supersedes the value this
+ * class's original author had to guess at from TS 102 687's undefined NDL_maxChannelUse.
+ */
+class DccInformationSharing : public DccFieldGenerator
+{
+public:
+    /**
+     * Create DCC_net instance
+     *
+     * \param rt Runtime for scheduling periodic update cycles
+     * \param lt Location Table with LocTEX_G5 entries
+     * \param target CBR_target value (usually NDL_maxChannelLoad)
+     * \param delay Delaying first update cycle randomly
+     *
+     * \note Set random delay interval when multiple stations are created at the same time!
+     *       Values shall be distributed uniformly across full integer range.
+     */
+    DccInformationSharing(Runtime& rt, const LocationTable& lt, dcc::ChannelLoad target, UnitInterval delay);
+    DccInformationSharing(Runtime& rt, const LocationTable& lt, dcc::ChannelLoad target);
+
+    DccField generate_dcc_field() override;
+
+    /**
+     * Update local CBR measurement
+     *
+     * Local measurement rate is decoupled from processing in DCC_net,
+     * i.e. DccInformationSharing buffers the given value and the latest
+     * measurement value when its internal update cycle runs.
+     *
+     * \param cbr local CBR measurement
+     */
+    void update_local_cbr(dcc::ChannelLoad cbr);
+
+    /**
+     * Set packet TX power
+     *
+     * \param power Packet transmission output power in dBm
+     */
+    void set_tx_power(unsigned power);
+
+private:
+    void trigger();
+
+    Runtime& m_runtime;
+    const LocationTable& m_location_table;
+    const dcc::ChannelLoad m_cbr_target;
+    dcc::ChannelLoad m_cbr_local;
+    unsigned m_tx_power;
+    CbrAggregator m_aggregator;
+    Clock::duration m_trigger_interval;
+    Timestamp m_last_aggregation;
+    Hook<const CbrAggregator&> m_update_hook;
+
+public:
+    /**
+     * on_global_cbr_update is called at each update cycle,
+     * i.e. when a new global CBR has been calculated
+     */
+    HookRegistry<const CbrAggregator&> on_global_cbr_update;
+};
+
+} // namespace geonet
+} // namespace vanetza
+
+#endif /* DCC_INFORMATION_SHARING_HPP_GZCSHZLD */
+