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/docs/idf/evidence/security-device-07/console.txt

@@ -0,0 +1,17 @@
+-- test_trust_domain_and_pool (free heap 111944, largest block 81920)
+-- test_signing_profiles (free heap 111676, largest block 81920)
+-- test_fail_closed (free heap 111676, largest block 81920)
+-- test_fail_closed: unknown issuer (free heap 111676, largest block 81920)
+-- test_fail_closed: expired ticket (free heap 111676, largest block 81920)
+-- test_fail_closed: SN-DECAP (free heap 111676, largest block 81920)
+-- test_identifier_change (free heap 111676, largest block 81920)
+-- test_gn_core_identifier_change (free heap 111676, largest block 81920)
+-- test_sf_facilities_hook (free heap 111676, largest block 81920)
+-- test_verification (free heap 111676, largest block 81920)
+-- verification cost: certificate-signed 35480 us (chain + message), digest-signed 35054 us (message only), ECDSA verify alone 29778 us
+-- test_chain_consistency (free heap 111676, largest block 81920)
+-- test_region_consistency (free heap 111448, largest block 63488)
+-- test_ecies (free heap 110616, largest block 31744)
+-- test_enrolment_and_authorization (free heap 110616, largest block 31744)
+PASS: 747 checks (host/component tests, not ETSI ATS verdicts)
+VIDF_TEST_RESULT=0

obu-firmware/external/vanetza-idf/docs/idf/evidence/security-device-07/result.json

@@ -0,0 +1,14 @@
+{
+  "kind": "component-tests",
+  "target": "esp32c5",
+  "idf_version": "6.0.2",
+  "port": "COM11",
+  "status": "pass",
+  "reset": "none",
+  "checks": 747,
+  "backend": "BackendMbedTls (PSA Crypto, mbedTLS 4.1.0 of ESP-IDF 6.0.2) with CONFIG_MBEDTLS_HARDWARE_ECDSA_VERIFY; 747 checks = 873 host checks minus the OpenSSL-only oracle tests",
+  "capture": "listen-only after the esptool post-flash reset",
+  "verifies": "receive-side verification (test_verification), the IEEE Std 1609.2 clause 5.1.2 chain consistency (test_chain_consistency) and the clause 6.4.17 region consistency under an identifiedRegion root (test_region_consistency) on the device; verification cost line: certificate-signed 35.5 ms, digest-signed 35.1 ms end to end, raw ECDSA P-256 verify 29.8 ms on the ECDSA peripheral",
+  "note": "the same checks appended to test_verification failed on the device only: with a fourth receiver trust configuration the heap was too fragmented (largest free block 16 kB) and an allocation failure inside verify() surfaced as INCOMPATIBLE_PROTOCOL through the catch-all; the chain and region scenarios therefore run as their own tests with a fresh heap and at most two stations alive",
+  "sha256": "20abb00efc091b27e7d43bf040967ffd808ca5a5e07d9ec6f0d3d9bee3cef7ec"
+}