fix: wrap Svelte HMR configureServer for vitest 3 compat

Vitest 3 bundles its own Vite which omits server.config.server,
causing the Svelte plugin's hot-update configureServer hook to
throw TypeError. Catches the error safely during test runs.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

dashboard/frontend/vitest.config.js

@@ -1,6 +1,31 @@
 import { defineConfig } from 'vitest/config';
 import { svelte } from '@sveltejs/vite-plugin-svelte';
 
+const sveltePlugin = svelte({
+  hot: !process.env.VITEST ? {
+    preserveLocalState: true
+  } : false,
+  compilerOptions: {
+    dev: true
+  }
+});
+
+// Vitest 3 bundles its own Vite which may not expose `server.config.server`,
+// causing the Svelte HMR plugin's configureServer to crash. Wrap it safely.
+if (process.env.VITEST) {
+  const plugins = Array.isArray(sveltePlugin) ? sveltePlugin : [sveltePlugin];
+  for (const p of plugins) {
+    if (p.configureServer) {
+      const orig = p.configureServer;
+      p.configureServer = function(server) {
+        try { return orig.call(this, server); } catch (e) {
+          if (!(e instanceof TypeError)) throw e;
+        }
+      };
+    }
+  }
+}
+
 export default defineConfig({
   plugins: [
     svelte({