refactor: modernize frontend with hoover framework components and docs

- Add quick modal, table, service status, and confirmation dialog components
- Refactor all pages (certs, dhcp, proxy, etc.) to use new component patterns
- Introduce refactor load utility and render guard for consistent UX
- Add hoover documentation and update AGENTS.md, architecture, overview

webui/static/index.html

@@ -14,6 +14,6 @@
     </div>
   </div>
   <script>window.__WS_URL__ = "__WS_URL_PLACEHOLDER__"</script>
-  <script type="module" src="/static/app.js?v=4"></script>
+  <script type="module" src="/static/app.js?v=6"></script>
 </body>
 </html>