build: Vite 单文件构建 + 修复 doubaoime-asr 打包后 WASM 加载失败

- vite.config.ts: codeSplitting: false 替代多 chunk 输出，产出单文件 dist/cli.js
- vite.config.ts: ssr.external 排除 doubaoime-asr/opus-encdec，避免 require.resolve 路径失效
- scripts/post-build.ts: 简化为直接处理单文件 dist/cli.js
- src/services/doubaoSTT.ts: 改进错误信息，输出具体异常内容便于排查

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

vite.config.ts

@@ -70,6 +70,11 @@ export default defineConfig({
   ssr: {
     target: 'node',
     noExternal: true,
+    // Packages with runtime require.resolve() or WASM binaries can't be
+    // inlined into the bundle — they must be resolved from node_modules
+    // at runtime.  doubaoime-asr uses opus-encdec which does
+    // require.resolve('opus-encdec/dist/libopus-encoder.wasm.js').
+    external: ['doubaoime-asr', 'opus-encdec'],
   },
 
   build: {
@@ -88,9 +93,9 @@ export default defineConfig({
 
       output: {
         format: 'es',
-        dir: 'dist',
+        // Single-file build: no code splitting, all dynamic imports inlined
+        codeSplitting: false,
         entryFileNames: 'cli.js',
-        chunkFileNames: 'chunks/[name]-[hash].js',
       },
 
       plugins: [