feat(#117): agent-count toasts and persistent error toast dismiss

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

ui/src/pages/AgentHealth/AgentHealth.tsx

@@ -11,6 +11,7 @@ import styles from './AgentHealth.module.css';
 import { useAgents, useAgentEvents } from '../../api/queries/agents';
 import { useApplicationLogs } from '../../api/queries/logs';
 import { useApplicationConfig, useUpdateApplicationConfig } from '../../api/queries/commands';
+import type { ConfigUpdateResponse } from '../../api/queries/commands';
 import type { AgentInstance } from '../../api/types';
 
 // ── Helpers ──────────────────────────────────────────────────────────────────
@@ -142,13 +143,18 @@ export default function AgentHealth() {
     if (!appConfig) return;
     const updated = { ...appConfig, ...configDraft };
     updateConfig.mutate(updated, {
-      onSuccess: (saved) => {
+      onSuccess: (saved: ConfigUpdateResponse) => {
         setConfigEditing(false);
         setConfigDraft({});
-        toast({ title: 'Config updated', description: `${appId} (v${saved.config.version})`, variant: 'success' });
+        if (saved.pushResult.success) {
+          toast({ title: 'Config updated', description: `${appId} (v${saved.config.version}) — pushed to ${saved.pushResult.total}/${saved.pushResult.total} agents`, variant: 'success' });
+        } else {
+          const failed = [...saved.pushResult.responses.filter(r => r.status !== 'SUCCESS').map(r => r.agentId), ...saved.pushResult.timedOut];
+          toast({ title: 'Config updated — partial push failure', description: `${saved.pushResult.responded}/${saved.pushResult.total} responded. Failed: ${failed.join(', ')}`, variant: 'warning', duration: 86_400_000 });
+        }
       },
       onError: () => {
-        toast({ title: 'Config update failed', variant: 'error' });
+        toast({ title: 'Config update failed', variant: 'error', duration: 86_400_000 });
       },
     });
   }, [appConfig, configDraft, updateConfig, toast, appId]);