fix(federation-ui): show trust-change failures inside the modal, not behind it

changeTrust() wrote failures into `error`, which renders inside <NodeList>
— page content that sits BEHIND the open NodeDetailModal. So when
promoting a peer to Trusted failed, the operator saw the dropdown snap
back and nothing else: the error banner was painted on a surface the
modal was covering. Reported as "the error doesn't show in the modal",
2026-08-09.

NodeDetailModal gains an actionError prop rendered directly under the
Trust Level control, and Federation.vue routes failures there whenever
that node's modal is open (clearing on close and on the next attempt).
The page banner still serves failures with no modal in the way, and the
password-retry path keeps its own in-modal error as before.

Verified: vue-tsc clean; federation component tests 5/5.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

neode-ui/src/views/Federation.vue

@@ -190,7 +190,8 @@
       :dwn-syncing="dwnSyncing"
       :deploying="deploying"
       :deploy-result="deployResult"
-      @close="selectedNode = null"
+      :action-error="nodeActionError"
+      @close="selectedNode = null; nodeActionError = ''"
       @change-trust="changeTrust"
       @remove-node="removeNode"
       @deploy-app="deployApp"
@@ -272,6 +273,9 @@ const nodesRes = useCachedResource<FederatedNode[]>({
 const nodes = computed(() => nodesRes.data.value ?? [])
 const loading = computed(() => nodesRes.loadState.value === 'loading')
 const error = ref('')
+/** Failure from an action taken inside NodeDetailModal (trust dropdown). Kept
+ *  separate from `error`, which renders in NodeList behind the modal. */
+const nodeActionError = ref('')
 const selectedNode = ref<FederatedNode | null>(null)
 const inviteType = ref<'trusted' | 'observer'>('trusted')
 
@@ -656,6 +660,7 @@ async function requestTrustChange(did: string, level: string, password?: string)
 }
 
 async function changeTrust(did: string, level: string) {
+  nodeActionError.value = ''
   try {
     await requestTrustChange(did, level)
   } catch (e) {
@@ -667,7 +672,12 @@ async function changeTrust(did: string, level: string) {
       )
       return
     }
-    error.value = e instanceof Error ? e.message : 'Failed to update trust level'
+    // Show the failure INSIDE the open modal. `error` renders in NodeList,
+    // which sits behind NodeDetailModal — so routing it there made a failed
+    // trust change look like the dropdown simply doing nothing.
+    const msg = e instanceof Error ? e.message : 'Failed to update trust level'
+    if (selectedNode.value?.did === did) nodeActionError.value = msg
+    else error.value = msg
   }
 }
 

neode-ui/src/views/federation/NodeDetailModal.vue

@@ -37,6 +37,7 @@
           <p class="text-xs text-white/40 mt-2">
             <span class="text-white/30">Granted via:</span> {{ trustSourceLabel }}
           </p>
+          <p v-if="actionError" class="text-xs text-red-400 mt-2" role="alert">{{ actionError }}</p>
         </div>
         <div class="bg-white/5 rounded-lg p-3">
           <p class="text-xs text-white/40 mb-1">Added</p>
@@ -146,6 +147,11 @@ const props = defineProps<{
   dwnSyncing: boolean
   deploying: boolean
   deployResult: string
+  /** Failure from an action taken INSIDE this modal (e.g. the trust dropdown).
+   *  Federation.vue used to route these to the page-level banner in NodeList,
+   *  which sits behind this modal — so a failed trust change looked like
+   *  nothing happening at all. */
+  actionError?: string
 }>()
 
 const emit = defineEmits<{