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-08/console.txt

@@ -0,0 +1,18 @@
+-- test_trust_domain_and_pool (free heap 107940, largest block 81920)
+-- test_signing_profiles (free heap 107672, largest block 81920)
+-- test_fail_closed (free heap 107672, largest block 81920)
+-- test_fail_closed: unknown issuer (free heap 107672, largest block 81920)
+-- test_fail_closed: expired ticket (free heap 107672, largest block 81920)
+-- test_fail_closed: SN-DECAP (free heap 107672, largest block 81920)
+-- test_identifier_change (free heap 107672, largest block 81920)
+-- test_gn_core_identifier_change (free heap 107672, largest block 81920)
+-- test_sf_facilities_hook (free heap 107672, largest block 81920)
+-- test_verification (free heap 107672, largest block 81920)
+-- verification cost: certificate-signed 35542 us (chain + message), digest-signed 34860 us (message only), ECDSA verify alone 29625 us
+-- test_chain_consistency (free heap 107672, largest block 81920)
+-- test_region_consistency (free heap 107432, largest block 45056)
+-- test_credentials (free heap 107188, largest block 36864)
+-- test_ecies (free heap 106568, largest block 36864)
+-- test_enrolment_and_authorization (free heap 106568, largest block 36864)
+PASS: 765 checks (host/component tests, not ETSI ATS verdicts)
+VIDF_TEST_RESULT=0

obu-firmware/external/vanetza-idf/docs/idf/evidence/security-device-08/result.json

@@ -0,0 +1,13 @@
+{
+  "kind": "component-tests",
+  "target": "esp32c5",
+  "idf_version": "6.0.2",
+  "port": "COM11",
+  "status": "pass",
+  "reset": "none",
+  "checks": 765,
+  "backend": "BackendMbedTls (PSA Crypto, mbedTLS 4.1.0 of ESP-IDF 6.0.2) with CONFIG_MBEDTLS_HARDWARE_ECDSA_VERIFY; 765 checks = 890 host checks minus the OpenSSL-only oracle tests",
+  "capture": "listen-only after the esptool post-flash reset",
+  "verifies": "as security-device-07 plus test_credentials: credential bundle round trip, malformed bundles refused, apply() through the entity's checks, NvsCredentialStore save/load/erase on the nvs_flash partition (CONFIG_VANETZA_IDF_NVS_CREDENTIALS=y, NVS initialised by the test application)",
+  "sha256": "ab9384f0150c90de84c5187a68363de4c13dc53781660cb4e8a473bdee69c3df"
+}