Keep the colleague's microbu-esp32c5 tree in this repository

obu-firmware builds against vanetza-idf from microbu-esp32c5/external, but
that tree was gitignored, so a clone of this repository could not build the
firmware it ships. It is now committed here as ordinary files in its own
folder, microbu-esp32c5/: the colleague's commit cf4b99f plus the V2X2MAP
bridge's signature verification (--trust) used on the bench. Nothing is
fetched from or pushed to the colleague's repository; this repository and
its remotes carry everything. The folder's own .gitignore keeps build output,
downloaded components and private key material out, as it did there; the
committed file set is identical to that repository's tracked files.

The ESP32-C5 is still flashed from obu-firmware/, which only takes
vanetza-idf from microbu-esp32c5/, so the two stay separate folders.
FLASHING.md says how to take a newer version of the colleague's tree (copy
it over the folder, rebuild, test, commit).

microbu-esp32c5/pki/uml-l0-rca/rca/certificate_report.json

@@ -0,0 +1,161 @@
+{
+  "id8": "AFD566A8034ED5DB",
+  "subject": {
+    "type": "hostname",
+    "hostname": "0_Urban-Mobility-Lab-Root-CA_L0"
+  },
+  "valid_from": "2026-09-14T23:58:51Z",
+  "valid_until": "2031-09-15T05:04:51Z",
+  "app_permissions": [
+    {
+      "type": "certificate_trust_list",
+      "tlm": false,
+      "root_ca": false,
+      "enrollment_authority": true,
+      "authorization_authority": true,
+      "distribution_centre": true
+    },
+    {
+      "type": "certificate_revocation_list"
+    }
+  ],
+  "cert_issue_permissions": [
+    {
+      "chain_length": {
+        "start": 2,
+        "end": 2
+      },
+      "end_entity_authorization": true,
+      "end_entity_enrollment": true,
+      "subject_permissions": {
+        "type": "explicit",
+        "permissions": [
+          {
+            "psid": "cam",
+            "auth": {
+              "type": "bitmap",
+              "subordinate_may_have": "01FFFF",
+              "subordinate_must_have": "FF0000"
+            }
+          },
+          {
+            "psid": "denm",
+            "auth": {
+              "type": "bitmap",
+              "subordinate_may_have": "02FFFFFFFF",
+              "subordinate_must_have": "FF00000000"
+            }
+          },
+          {
+            "psid": "tlm",
+            "auth": {
+              "type": "bitmap",
+              "subordinate_may_have": "01E0",
+              "subordinate_must_have": "FF1F"
+            }
+          },
+          {
+            "psid": "rlt",
+            "auth": {
+              "type": "bitmap",
+              "subordinate_may_have": "01C0",
+              "subordinate_must_have": "FF3F"
+            }
+          },
+          {
+            "psid": "ivim",
+            "auth": {
+              "type": "bitmap",
+              "subordinate_may_have": "01000000FFFF",
+              "subordinate_must_have": "FF0000000000"
+            }
+          },
+          {
+            "psid": "tlc_req",
+            "auth": {
+              "type": "bitmap",
+              "subordinate_may_have": "02FFFFE0",
+              "subordinate_must_have": "FF00001F"
+            }
+          },
+          {
+            "psid": "gm_mgmt",
+            "auth": {
+              "type": "all"
+            }
+          },
+          {
+            "psid": "cert_req",
+            "auth": {
+              "type": "bitmap",
+              "subordinate_may_have": "01C0",
+              "subordinate_must_have": "FF3F"
+            }
+          },
+          {
+            "psid": "tlc_stat",
+            "auth": {
+              "type": "bitmap",
+              "subordinate_may_have": "01",
+              "subordinate_must_have": "FF"
+            }
+          },
+          {
+            "psid": "vru",
+            "auth": {
+              "type": "bitmap",
+              "subordinate_may_have": "01",
+              "subordinate_must_have": "FF"
+            }
+          },
+          {
+            "psid": "cp",
+            "auth": {
+              "type": "bitmap",
+              "subordinate_may_have": "01",
+              "subordinate_must_have": "FF"
+            }
+          },
+          {
+            "psid": "poi",
+            "auth": {
+              "type": "bitmap",
+              "subordinate_may_have": "01",
+              "subordinate_must_have": "FF"
+            }
+          }
+        ]
+      }
+    },
+    {
+      "chain_length": {
+        "start": 1,
+        "end": 1
+      },
+      "end_entity_authorization": true,
+      "end_entity_enrollment": false,
+      "subject_permissions": {
+        "type": "explicit",
+        "permissions": [
+          {
+            "psid": "cert_req",
+            "auth": {
+              "type": "bitmap",
+              "subordinate_may_have": "013E",
+              "subordinate_must_have": "FFC1"
+            }
+          }
+        ]
+      }
+    }
+  ],
+  "cert_request_permissions": [],
+  "signature": {
+    "type": "self_signed",
+    "verifies": true
+  },
+  "public_key": {
+    "curve": "nistP256",
+    "k": "0245162C40C3C5FFAF8C65FE5983786C9F2319477F56DA2D6B6EEB049BFEEF0C75"
+  }
+}