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/components/layout/TopNav.tsx

@@ -0,0 +1,44 @@
+import { NavLink } from 'react-router';
+import { useThemeStore } from '../../theme/theme-store';
+import { useAuthStore } from '../../auth/auth-store';
+import styles from './TopNav.module.css';
+
+export function TopNav() {
+  const { theme, toggle } = useThemeStore();
+  const { username, logout } = useAuthStore();
+
+  return (
+    <nav className={styles.topnav}>
+      <NavLink to="/" className={styles.logo}>
+        <svg width="22" height="22" viewBox="0 0 24 24" fill="none" stroke="currentColor" strokeWidth="2" strokeLinecap="round" strokeLinejoin="round">
+          <path d="M12 2C6.5 2 2 6.5 2 12s4.5 10 10 10 10-4.5 10-10S17.5 2 12 2" />
+          <path d="M12 6v6l4 2" />
+        </svg>
+        cameleer3
+      </NavLink>
+
+      <ul className={styles.navLinks}>
+        <li>
+          <NavLink to="/executions" className={({ isActive }) => isActive ? styles.navLinkActive : styles.navLink}>
+            Transactions
+          </NavLink>
+        </li>
+      </ul>
+
+      <div className={styles.navRight}>
+        <span className={styles.envBadge}>PRODUCTION</span>
+        <button className={styles.themeToggle} onClick={toggle} title="Toggle theme">
+          {theme === 'dark' ? '\u2600\uFE0F' : '\uD83C\uDF19'}
+        </button>
+        {username && (
+          <span className={styles.userInfo}>
+            {username}
+            <button className={styles.logoutBtn} onClick={logout} title="Sign out">
+              &#x2715;
+            </button>
+          </span>
+        )}
+      </div>
+    </nav>
+  );
+}