Keep the path attributes of rejected routes, and show them

A rejected route was recorded with its prefix, reason and AS path, which
is not enough to tell why a neighbor sent it: whether a /32 is a
blackhole request, which communities a leaked route carries, which
network marked it Only to Customer.

Each recorded rejection now keeps the attributes of the UPDATE it came
in, without the NLRI of MP_REACH_NLRI and MP_UNREACH_NLRI, and its next
hop. The attributes are copied once per UPDATE, only when a route of it
is rejected, and shared by its rejected routes. A route rejected later,
when the RPKI data changes, has the attributes it was stored with.

/api/routes/rejected gives them as `summary` and `attributes`, as for
received routes, and the status page shows them under "show" in each
row of the refused routes.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

docs/content/docs/operations/monitoring.md

@@ -70,10 +70,12 @@ curl -s '127.0.0.1:8080/api/routes/received?address=193.0.0.1&best=true' | jq
 
 Ferrix does not store rejected routes in the routing table. For each
 neighbor, it records the number of rejected routes for each reason, and the
-200 most recent rejected routes with their AS paths. The status page
-displays this information under "Refused routes", and the HTTP endpoint
-`/api/routes/rejected` returns it as JSON. To display the records for one
-neighbor, add `?peer=NAME`.
+200 most recent rejected routes with all the path attributes they were
+received with. The status page displays this information under "Refused
+routes"; to display the attributes of a rejected route, select **show** in
+its row. The HTTP endpoint `/api/routes/rejected` returns the same
+information as JSON. To display the records for one neighbor, add
+`?peer=NAME`.
 
 ```json
 [{"peer":"transit-a","total":3,"by_reason":{"RPKI invalid":2,"bogon prefix":1},

docs/content/docs/reference/http-api.md

@@ -143,11 +143,29 @@ routes. To return the records for one neighbor, add `?peer=NAME`.
     "path_id": 0,
     "reason": "own AS in path",
     "as_path": [65001, 64500],
-    "at_unix": 1791020702
+    "at_unix": 1791020702,
+    "summary": {
+      "origin": "IGP",
+      "as_path": [65001, 64500],
+      "next_hop": "10.0.0.2",
+      "med": null,
+      "local_pref": null,
+      "communities": [],
+      "large_communities": []
+    },
+    "attributes": [
+      { "Origin": 0 },
+      { "AsPath": { "segments": [{ "ordered": true, "path": [65001, 64500] }] } },
+      { "NextHop": "10.0.0.2" }
+    ]
   }]
 }]
 ```
 
+| Field | Description |
+|---|---|
+| `summary`, `attributes` | The path attributes of the rejected route, in the same format as for received routes. For a route rejected when RPKI data changed, the attributes as stored, including those added by the import policy. |
+
 ## Kernel
 
 `/api/kernel` returns the state of kernel route installation: