fix(demo): keep build output out of demo sources

Write the built demo to demo/dist instead of demo/ so build-demo no longer deletes the checked-in demo source files.

Also switch the demo image reference to use new URL(..., import.meta.url).href, which avoids the TypeScript 5.9 asset import resolution failure seen in CI during check-types.

Add a regression test for the demo build config and ignore only demo/dist.

Author: nygardk

.gitignore

@@ -2,5 +2,5 @@
 node_modules/
 dist/
 coverage/
-demo/
+demo/dist/
 *.log

demo/Demo.tsx

@@ -51,7 +51,8 @@ import {
 } from '../src';
 
 import './Demo.css';
-import exampleImage from './react-share-pin-example.png';
+
+const exampleImage = new URL('./react-share-pin-example.png', import.meta.url).href;
 
 export function Demo() {
   const shareUrl = 'http://github.com';

test/DemoBuildConfig.test.ts

@@ -0,0 +1,16 @@
+import { readFile } from 'node:fs/promises';
+import path from 'node:path';
+import { fileURLToPath } from 'node:url';
+import { describe, expect, it } from 'vitest';
+
+describe('demo build config', () => {
+  it('writes built assets under demo/dist without overwriting demo sources', async () => {
+    const workspaceRoot = path.resolve(path.dirname(fileURLToPath(import.meta.url)), '..');
+    const configPath = path.join(workspaceRoot, 'vite.demo.config.js');
+    const configSource = await readFile(configPath, 'utf8');
+
+    expect(configSource).toContain("root: './demo'");
+    expect(configSource).toContain("outDir: './dist'");
+    expect(configSource).not.toContain("outDir: '../demo'");
+  });
+});

vite.demo.config.js

@@ -5,7 +5,7 @@ export default defineConfig({
   root: './demo',
   plugins: [react()],
   build: {
-    outDir: '../demo',
+    outDir: './dist',
     emptyOutDir: true,
     cssMinify: false,
   },