fix(examples): TypeScript in with-svelte example (#10450)

### Description

Inspired by @DoctorRyner in #10437, a set of changes to make TypeScript
work better for the `with-svelte` example.

### Testing Instructions

This set of changes works correctly in my editor.

---------

Co-authored-by: Rainer Reinhardt <[email protected]>

Author: anthonyshew

examples/with-svelte/packages/ui/package.json

@@ -3,8 +3,8 @@
   "version": "0.0.0",
   "type": "module",
   "scripts": {
-    "dev": "svelte-package --watch --input=src",
-    "build": "svelte-package --input=src",
+    "dev": "svelte-kit sync && svelte-package --watch --input=src",
+    "build": "svelte-kit sync && svelte-package --input=src",
     "lint": "eslint .",
     "check-types": "svelte-check --tsconfig ./tsconfig.json"
   },
@@ -31,6 +31,7 @@
   "devDependencies": {
     "@repo/eslint-config": "workspace:*",
     "@repo/typescript-config": "workspace:*",
+    "@sveltejs/kit": "^2.20.0",
     "@sveltejs/package": "^2.0.0",
     "@sveltejs/vite-plugin-svelte": "^5.0.0",
     "eslint": "^9.25.0",

examples/with-svelte/packages/ui/svelte.config.js

@@ -0,0 +1,10 @@
+import { vitePreprocess } from '@sveltejs/vite-plugin-svelte';
+
+/** @type {import('@sveltejs/kit').Config} */
+const config = {
+  // Consult https://kit.svelte.dev/docs/integrations#preprocessors
+  // for more information about preprocessors
+  preprocess: vitePreprocess()
+};
+
+export default config;

examples/with-svelte/packages/ui/tsconfig.json

@@ -1,15 +1,10 @@
 {
-  "extends": "@repo/typescript-config/svelte.json",
+  "extends": ["@repo/typescript-config/svelte.json", "./.svelte-kit/tsconfig.json"],
   "compilerOptions": {
     "declaration": true,
     "declarationMap": true,
+    "allowArbitraryExtensions": true
   },
-  "include": [
-    "src"
-  ],
-  "exclude": [
-    "node_modules",
-    "dist",
-    ".svelte-kit"
-  ]
-}
+  "include": ["dist", "./src/**/*.svelte", "./src/**/*.ts"],
+  "exclude": ["node_modules", ".svelte-kit"]
+}