refactor: 架构整固——分层单向化、全量 TypeScript、直接运行

- 移除 bd/mg 两平台及磁盘残留产物；清理 api-test 死脚本、musicSdk/message+options 死模块、infSign vendor
- musicSdk/ 改名 sdk/；src/common、src/auth、src/apis 整体移入 sdk/，依赖方向定为 src → sdk 严格单向
- src/ 手写 JS 全量转 .ts，删除 JS 类型垫片 modules.d.ts；源码 import 统一 .ts 后缀
- Node 原生类型剥离直接运行 .ts（engines >=22.18），取消 tsc 发射产物，tsc 仅类型检查（pnpm typecheck）
- 删除 kwdes 备用实现与 src/index.ts 转发垫片；测试移至 test/smoke-test.ts
- common/request.ts 补显式导出类型；修复 set-cookie 单值形态、ApiError 类字段等隐患

验证：tsc 零错误，smoke-test 41/41

sdk/wy/musicInfo.ts

@@ -0,0 +1,25 @@
+// https://github.com/Binaryify/NeteaseCloudMusicApi/blob/master/module/song_detail.js
+import { httpFetch } from '../request.ts'
+import { weapi } from './utils/crypto.ts'
+import type { RequestObj } from '../types.ts'
+
+export default (songmid: string): RequestObj<any> => {
+  const requestObj = httpFetch('https://music.163.com/weapi/v3/song/detail', {
+    method: 'post',
+    headers: {
+      'User-Agent': 'Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/60.0.3112.90 Safari/537.36',
+      Referer: 'https://music.163.com/song?id=' + songmid,
+      origin: 'https://music.163.com',
+    },
+    form: weapi({
+      c: `[{"id":${songmid}}]`,
+      ids: `[${songmid}]`,
+    }),
+  })
+  requestObj.promise = requestObj.promise.then(({ body }) => {
+    // console.log(body)
+    if (body.code !== 200 || !body.songs.length) return Promise.reject(new Error('获取歌曲信息失败'))
+    return body.songs[0]
+  })
+  return requestObj
+}