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/security/v3/geometry.hpp

@@ -0,0 +1,63 @@
+#pragma once
+#include <vanetza/security/v3/asn1_types.hpp>
+
+namespace vanetza
+{
+
+// forward declaration
+struct PositionFix;
+
+namespace security
+{
+namespace v3
+{
+
+/**
+ * Check if a TwoDLocation is valid
+ * 
+ * \param location TwoDLocation to be checked
+ * \return true if latitude and longitude are within valid range
+ */
+bool is_valid(const asn1::TwoDLocation& location);
+
+/**
+ * Check if position is inside a circular region
+ * 
+ * \param pos position to be checked
+ * \param region circular region
+ * \return true if position is inside region
+ */
+bool is_inside(const PositionFix& pos, const asn1::CircularRegion& region);
+
+/**
+ * Check if position is inside at least one of the given regions
+ * 
+ * \param pos position to be checked
+ * \param regions sequence of rectangular regions
+ * \return true if position is inside at least one region
+ */
+bool is_inside(const PositionFix& pos, const asn1::SequenceOfRectangularRegion& region);
+
+/**
+ * Check if position is inside a rectangular region
+ * 
+ * \param pos position to be checked
+ * \param region rectangular region
+ * \return true if position is inside region
+ */
+bool is_inside(const PositionFix& pos, const asn1::RectangularRegion& region);
+
+/**
+ * \brief Check if a location is inside a polygonal region.
+ *
+ * \param location The location to check.
+ * \param region The polygonal region to check against.
+ * \return true if the location is inside the region, false otherwise.
+ */
+bool is_inside(const PositionFix& location, const asn1::PolygonalRegion& region);
+bool is_inside(const asn1::TwoDLocation* location, const asn1::PolygonalRegion* region);
+
+} // namespace v3
+} // namespace security
+} // namespace vanetza
+