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>

cameleer3-server-app/src/main/java/com/cameleer3/server/app/web/SpaForwardController.java

@@ -0,0 +1,24 @@
+package com.cameleer3.server.app.web;
+
+import org.springframework.stereotype.Controller;
+import org.springframework.web.bind.annotation.GetMapping;
+
+/**
+ * SPA catch-all: forwards non-API, non-static requests to {@code index.html}
+ * so that React Router can handle client-side routing.
+ * <p>
+ * Only active when the UI is embedded (i.e., {@code static/index.html} exists
+ * in the classpath). When running standalone via Nginx, this is not needed.
+ */
+@Controller
+public class SpaForwardController {
+
+    @GetMapping(value = {
+            "/login",
+            "/executions",
+            "/executions/{path:[^\\.]*}"
+    })
+    public String forward() {
+        return "forward:/index.html";
+    }
+}