swarm-ui: show a failed wanted-state change in the agent details

The failure was recorded but only the roster card drew it, so the details dialog on a terminal page said nothing when a declaration failed. AgentDetail now shows it under the wanted menu, which the roster's detail panel gets too.

frontend/packages/swarm-ui/src/pages/agents/AgentDetail.tsx

@@ -6,6 +6,7 @@
 //
 // Takes the agent's *live* row and the shared `AgentActions`, so a state
 // change or a link made here shows wherever else the same row is drawn.
+import { ApiErrorPanel } from "@hive/shared/api-error-panel.js";
 import { Badge } from "@hive/shared/badge.js";
 import { RelativeTime } from "../../ui/relative-time/RelativeTime.js";
 import type { AgentActions } from "./AgentActions.js";
@@ -28,6 +29,7 @@ export function AgentDetail({
   withTerminal?: boolean;
 }) {
   const { tone, label } = FRESHNESS[row.freshness];
+  const declareError = actions.actionErrors.get(row.name);
   return (
     <div class="ui-agent-detail">
       <dl class="ui-agent-detail-fields">
@@ -62,6 +64,14 @@ export function AgentDetail({
             onSelectPaused={actions.selectPaused}
             onDestroy={actions.requestDestroy}
           />
+          {/* A failed declaration shows here too: on a terminal page's
+              dialog there is no roster card to carry the "failed" badge. */}
+          {declareError ? (
+            <ApiErrorPanel
+              context="the declaration failed"
+              problem={declareError}
+            />
+          ) : null}
         </dd>
         <dt>hive</dt>
         <dd>{row.hive ?? "—"}</dd>