Add build script

scripts/build.mjs

@@ -0,0 +1,43 @@
+// No bundler: copy the app and the phonon-tts package into dist/, then write
+// the service worker's precache list. phonon-tts is plain ES modules.
+import { cpSync, rmSync, mkdirSync, readdirSync, statSync, readFileSync, writeFileSync, existsSync } from 'node:fs';
+import { join, relative } from 'node:path';
+import { createHash } from 'node:crypto';
+import { execSync } from 'node:child_process';
+
+const root = new URL('..', import.meta.url).pathname;
+const dist = join(root, 'dist');
+const pkg = join(root, 'node_modules', 'phonon-tts');
+if (!existsSync(pkg)) execSync('npm install --no-audit --no-fund', { cwd: root, stdio: 'inherit' });
+
+rmSync(dist, { recursive: true, force: true });
+mkdirSync(dist);
+cpSync(join(root, 'index.html'), join(dist, 'index.html'));
+cpSync(join(root, 'src'), join(dist, 'src'), { recursive: true });
+cpSync(join(root, 'public'), dist, { recursive: true });
+
+const vendor = join(dist, 'vendor', 'phonon-tts');
+mkdirSync(vendor, { recursive: true });
+for (const f of readdirSync(pkg)) {
+  if (f.endsWith('.js') || f === 'wasm' || f === 'wasm-threads' || f.startsWith('LICENSE') || f === 'THIRD_PARTY_LICENSES.md') {
+    cpSync(join(pkg, f), join(vendor, f), { recursive: true, filter: (s) => !s.endsWith('.d.ts') });
+  }
+}
+
+const files = [];
+const walk = (d) => readdirSync(d).forEach((n) => { const p = join(d, n); statSync(p).isDirectory() ? walk(p) : files.push(p); });
+walk(dist);
+const hash = createHash('sha256');
+const urls = [];
+for (const f of files.sort()) {
+  const rel = relative(dist, f).split('\\').join('/');
+  if (rel === 'sw.js' || rel.endsWith('.md') || rel.includes('LICENSE')) continue;
+  hash.update(rel).update(readFileSync(f));
+  urls.push('./' + rel);
+}
+urls.push('./');
+const swPath = join(dist, 'sw.js');
+writeFileSync(swPath, readFileSync(swPath, 'utf8')
+  .replace('__PRECACHE__', JSON.stringify(urls))
+  .replace('__VERSION__', hash.digest('hex').slice(0, 12)));
+console.log(`built dist/ — precaching ${urls.length} files`);