Add browser-local Piper WebAssembly speech

scripts/build-piper.mjs

@@ -0,0 +1,51 @@
+import {build} from 'esbuild';
+import {cp, mkdir, readdir, rm, stat} from 'node:fs/promises';
+import {join, resolve} from 'node:path';
+
+const root = process.cwd();
+const publicRoot = join(root, 'public');
+const assetRoot = join(publicRoot, 'tts', 'piper-wasm-v1');
+const onnxSource = join(root, 'node_modules', 'onnxruntime-web', 'dist');
+const piperSource = join(root, 'node_modules', '@diffusionstudio', 'piper-wasm', 'build');
+const piperWasm = join(piperSource, 'piper_phonemize.wasm');
+const piperData = join(piperSource, 'piper_phonemize.data');
+
+await rm(assetRoot, {recursive: true, force: true});
+await mkdir(join(assetRoot, 'onnx'), {recursive: true});
+await mkdir(join(assetRoot, 'piper'), {recursive: true});
+
+const wasmFiles = (await readdir(onnxSource))
+  .filter(name => name.endsWith('.wasm'));
+if (wasmFiles.length === 0) throw new Error('ONNX Runtime WebAssembly files are missing');
+for (const file of wasmFiles) {
+  await cp(join(onnxSource, file), join(assetRoot, 'onnx', file));
+}
+for (const file of [piperWasm, piperData]) {
+  const fileStat = await stat(file).catch(() => null);
+  if (!fileStat?.isFile() || fileStat.size === 0) throw new Error(`Missing Piper WebAssembly asset: ${file}`);
+  await cp(file, join(assetRoot, 'piper', file.split('/').at(-1)));
+}
+
+await build({
+  entryPoints: [resolve(root, 'piper-runtime.js')],
+  outfile: join(publicRoot, 'piper-runtime.js'),
+  bundle: true,
+  format: 'iife',
+  platform: 'browser',
+  target: ['es2022'],
+  sourcemap: false,
+  legalComments: 'none',
+});
+
+await build({
+  entryPoints: [resolve(root, 'piper-worker.js')],
+  outfile: join(assetRoot, 'piper-worker.js'),
+  bundle: true,
+  format: 'iife',
+  platform: 'browser',
+  target: ['es2022'],
+  sourcemap: false,
+  legalComments: 'none',
+});
+
+console.log(`Piper browser assets prepared at ${assetRoot}`);