Add React UI with Execution Explorer, auth, and standalone deployment

- Scaffold Vite + React + TypeScript frontend in ui/ with full design
  system (dark/light themes) matching the HTML mockups
- Implement Execution Explorer page: search filters, results table with
  expandable processor tree and exchange detail sidebar, pagination
- Add UI authentication: UiAuthController (login/refresh endpoints),
  JWT filter handles ui: subject prefix, CORS configuration
- Shared components: StatusPill, DurationBar, StatCard, AppBadge,
  FilterChip, Pagination — all using CSS Modules with design tokens
- API client layer: openapi-fetch with auth middleware, TanStack Query
  hooks for search/detail/snapshot queries, Zustand for state
- Standalone deployment: Nginx Dockerfile, K8s Deployment + ConfigMap +
  NodePort (30080), runtime config.js for API base URL
- Embedded mode: maven-resources-plugin copies ui/dist into JAR static
  resources, SPA forward controller for client-side routing
- CI/CD: UI build step, Docker build/push for server-ui image, K8s
  deploy step for UI, UI credential secrets

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

ui/src/api/queries/agents.ts

@@ -0,0 +1,15 @@
+import { useQuery } from '@tanstack/react-query';
+import { api } from '../client';
+
+export function useAgents(status?: string) {
+  return useQuery({
+    queryKey: ['agents', status],
+    queryFn: async () => {
+      const { data, error } = await api.GET('/agents', {
+        params: { query: status ? { status } : {} },
+      });
+      if (error) throw new Error('Failed to load agents');
+      return data!;
+    },
+  });
+}

ui/src/api/queries/executions.ts

@@ -0,0 +1,53 @@
+import { useQuery } from '@tanstack/react-query';
+import { api } from '../client';
+import type { SearchRequest } from '../schema';
+
+export function useSearchExecutions(filters: SearchRequest) {
+  return useQuery({
+    queryKey: ['executions', 'search', filters],
+    queryFn: async () => {
+      const { data, error } = await api.POST('/search/executions', {
+        body: filters,
+      });
+      if (error) throw new Error('Search failed');
+      return data!;
+    },
+    placeholderData: (prev) => prev,
+  });
+}
+
+export function useExecutionDetail(executionId: string | null) {
+  return useQuery({
+    queryKey: ['executions', 'detail', executionId],
+    queryFn: async () => {
+      const { data, error } = await api.GET('/executions/{executionId}', {
+        params: { path: { executionId: executionId! } },
+      });
+      if (error) throw new Error('Failed to load execution detail');
+      return data!;
+    },
+    enabled: !!executionId,
+  });
+}
+
+export function useProcessorSnapshot(
+  executionId: string | null,
+  index: number | null,
+) {
+  return useQuery({
+    queryKey: ['executions', 'snapshot', executionId, index],
+    queryFn: async () => {
+      const { data, error } = await api.GET(
+        '/executions/{executionId}/processors/{index}/snapshot',
+        {
+          params: {
+            path: { executionId: executionId!, index: index! },
+          },
+        },
+      );
+      if (error) throw new Error('Failed to load snapshot');
+      return data!;
+    },
+    enabled: !!executionId && index !== null,
+  });
+}