feat: UI/UX redesign for MCP Apps - 3 new apps + enhanced existing (#583)

Add workflow-list, execution-history, and health-dashboard apps.
Redesign operation-result with operation-aware headers, detail panels,
and copy-to-clipboard. Fix React hooks violations in validation-summary
and execution-history (useMemo after early returns). Add local preview
harness for development. Update tests for 5-app config.

Conceived by Romuald Członkowski - www.aiadvisors.pl/en

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

src/mcp/ui/app-configs.ts

@@ -29,4 +29,34 @@ export const UI_APP_CONFIGS: UIAppConfig[] = [
       'n8n_validate_workflow',
     ],
   },
+  {
+    id: 'workflow-list',
+    displayName: 'Workflow List',
+    description: 'Compact table of workflows with status, tags, and metadata',
+    uri: 'ui://n8n-mcp/workflow-list',
+    mimeType: 'text/html;profile=mcp-app',
+    toolPatterns: [
+      'n8n_list_workflows',
+    ],
+  },
+  {
+    id: 'execution-history',
+    displayName: 'Execution History',
+    description: 'Execution history table with status summary bar',
+    uri: 'ui://n8n-mcp/execution-history',
+    mimeType: 'text/html;profile=mcp-app',
+    toolPatterns: [
+      'n8n_executions',
+    ],
+  },
+  {
+    id: 'health-dashboard',
+    displayName: 'Health Dashboard',
+    description: 'Connection status, versions, and performance metrics',
+    uri: 'ui://n8n-mcp/health-dashboard',
+    mimeType: 'text/html;profile=mcp-app',
+    toolPatterns: [
+      'n8n_health_check',
+    ],
+  },
 ];