feat: add VC verification status to federation node list

- federation.list-nodes now includes vc_verified: bool per node
- True when a non-revoked FederationTrustCredential exists for the peer DID
- Integrates with VC-02's automatic VC issuance on federation join

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

core/archipelago/src/api/rpc/federation.rs

@@ -146,10 +146,26 @@ impl RpcHandler {
         }))
     }
 
-    /// federation.list-nodes — List all federated nodes with their status and last state.
+    /// federation.list-nodes — List all federated nodes with their status, last state, and VC verification.
     pub(super) async fn handle_federation_list_nodes(&self) -> Result<serde_json::Value> {
         let nodes = federation::load_nodes(&self.config.data_dir).await?;
 
+        // Load credentials to check for federation VCs
+        let cred_store = credentials::load_credentials(&self.config.data_dir).await.ok();
+        let vc_subjects: std::collections::HashSet<String> = cred_store
+            .as_ref()
+            .map(|s| {
+                s.credentials
+                    .iter()
+                    .filter(|vc| {
+                        vc.credential_type.iter().any(|t| t == "FederationTrustCredential")
+                            && !credentials::is_revoked(vc)
+                    })
+                    .map(|vc| vc.credential_subject.id.clone())
+                    .collect()
+            })
+            .unwrap_or_default();
+
         let nodes_json: Vec<serde_json::Value> = nodes
             .iter()
             .map(|n| {
@@ -159,6 +175,7 @@ impl RpcHandler {
                     "onion": n.onion,
                     "trust_level": n.trust_level.to_string(),
                     "added_at": n.added_at,
+                    "vc_verified": vc_subjects.contains(&n.did),
                 });
                 if let Some(name) = &n.name {
                     obj["name"] = serde_json::json!(name);