feat(ui): brancher le design system (exports ESM, Font Awesome, polices offline)

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

client/src/components/ui-kit.tsx

@@ -656,3 +656,9 @@ Object.assign(window, {
   `;
   document.head.appendChild(s);
 })();
+
+export {
+  Icon, Tooltip, IconButton, Toggle, StatusLed,
+  BatteryGauge, RadialGauge, BigRadialGauge,
+  Popup, Button, TreeNav, Sparkline, LineChart,
+};

client/src/main.tsx

@@ -1,5 +1,9 @@
 import React from "react";
 import { createRoot } from "react-dom/client";
+import "@fortawesome/fontawesome-free/css/all.min.css";
+import "@fontsource/inter";
+import "@fontsource/jetbrains-mono";
+import "@fontsource/share-tech-mono";
 import "./styles/app.css";
 import { App } from "./App.js";