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/kg/lyric.ts

@@ -0,0 +1,108 @@
+import { httpFetch } from '../request.ts'
+import { decodeKrc } from '../common/lyricUtils/kg.ts'
+
+export default {
+  getIntv(interval) {
+    if (!interval) return 0
+    let intvArr = interval.split(':')
+    let intv = 0
+    let unit = 1
+    while (intvArr.length) {
+      intv += (intvArr.pop()) * unit
+      unit *= 60
+    }
+    return parseInt(intv as unknown as string)
+  },
+  // getLyric(songInfo, tryNum = 0) {
+  //   let requestObj = httpFetch(`http://m.kugou.com/app/i/krc.php?cmd=100&keyword=${encodeURIComponent(songInfo.name)}&hash=${songInfo.hash}&timelength=${songInfo._interval || this.getIntv(songInfo.interval)}&d=0.38664927426725626`, {
+  //     headers: {
+  //       'KG-RC': 1,
+  //       'KG-THash': 'expand_search_manager.cpp:852736169:451',
+  //       'User-Agent': 'KuGou2012-9020-ExpandSearchManager',
+  //     },
+  //   })
+  //   requestObj.promise = requestObj.promise.then(({ body, statusCode }) => {
+  //     if (statusCode !== 200) {
+  //       if (tryNum > 5) return Promise.reject(new Error('歌词获取失败'))
+  //       let tryRequestObj = this.getLyric(songInfo, ++tryNum)
+  //       requestObj.cancelHttp = tryRequestObj.cancelHttp.bind(tryRequestObj)
+  //       return tryRequestObj.promise
+  //     }
+  //     return {
+  //       lyric: body,
+  //       tlyric: '',
+  //     }
+  //   })
+  //   return requestObj
+  // },
+  searchLyric(name, hash, time, tryNum = 0) {
+    let requestObj = httpFetch(`http://lyrics.kugou.com/search?ver=1&man=yes&client=pc&keyword=${encodeURIComponent(name)}&hash=${hash}&timelength=${time}&lrctxt=1`, {
+      headers: {
+        'KG-RC': '1',
+        'KG-THash': 'expand_search_manager.cpp:852736169:451',
+        'User-Agent': 'KuGou2012-9020-ExpandSearchManager',
+      },
+    })
+    requestObj.promise = (requestObj.promise as any).then(({ body, statusCode }) => {
+      if (statusCode !== 200) {
+        if (tryNum > 5) return Promise.reject(new Error('歌词获取失败'))
+        let tryRequestObj = this.searchLyric(name, hash, time, ++tryNum)
+        requestObj.cancelHttp = tryRequestObj.cancelHttp.bind(tryRequestObj)
+        return tryRequestObj.promise
+      }
+      if (body.candidates.length) {
+        let info = body.candidates[0]
+        return { id: info.id, accessKey: info.accesskey, fmt: (info.krctype == 1 && info.contenttype != 1) ? 'krc' : 'lrc' }
+      }
+      return null
+    })
+    return requestObj
+  },
+  getLyricDownload(id, accessKey, fmt, tryNum = 0) {
+    let requestObj = httpFetch(`http://lyrics.kugou.com/download?ver=1&client=pc&id=${id}&accesskey=${accessKey}&fmt=${fmt}&charset=utf8`, {
+      headers: {
+        'KG-RC': '1',
+        'KG-THash': 'expand_search_manager.cpp:852736169:451',
+        'User-Agent': 'KuGou2012-9020-ExpandSearchManager',
+      },
+    })
+    requestObj.promise = (requestObj.promise as any).then(({ body, statusCode }) => {
+      if (statusCode !== 200) {
+        if (tryNum > 5) return Promise.reject(new Error('歌词获取失败'))
+        let tryRequestObj = (this.getLyric as any)(id, accessKey, fmt, ++tryNum)
+        requestObj.cancelHttp = tryRequestObj.cancelHttp.bind(tryRequestObj)
+        return tryRequestObj.promise
+      }
+
+      switch (body.fmt) {
+        case 'krc':
+          return decodeKrc(body.content)
+        case 'lrc':
+          return {
+            lyric: Buffer.from(body.content, 'base64').toString('utf-8'),
+            tlyric: '',
+            rlyric: '',
+            yrc: '',
+          }
+        default:
+          return Promise.reject(new Error(`未知歌词格式: ${body.fmt}`))
+      }
+    })
+
+    return requestObj
+  },
+  getLyric(songInfo, tryNum = 0) {
+    let requestObj = this.searchLyric(songInfo.name, songInfo.hash, songInfo._interval || this.getIntv(songInfo.interval))
+
+    requestObj.promise = requestObj.promise.then(result => {
+      if (!result) return Promise.reject(new Error('Get lyric failed'))
+
+      let requestObj2 = this.getLyricDownload((result as any).id, (result as any).accessKey, (result as any).fmt)
+
+      requestObj.cancelHttp = requestObj2.cancelHttp.bind(requestObj2)
+
+      return requestObj2.promise
+    }) as any
+    return requestObj
+  },
+}