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/util.ts

@@ -0,0 +1,48 @@
+import { toMD5 } from '../utils.ts'
+import { httpFetch } from '../request.ts'
+import type { HttpOptions } from '../types.ts'
+
+// s.content[0].lyricContent.forEach(([str]) => {
+//   console.log(str)
+// })
+
+/**
+ * 签名
+ * @param {*} params
+ * @param {*} apiver
+ */
+export const signatureParams = (params: string, platform = 'android', body = ''): string => {
+  let keyparam = 'OIlwieks28dk2k092lksi2UIkp'
+  if (platform === 'web') keyparam = 'NVPh5oo715z5DIWAeQlhMDsWXXQV4hwt'
+  let param_list = params.split('&')
+  param_list.sort()
+  let sign_params = `${keyparam}${param_list.join('')}${body}${keyparam}`
+  return toMD5(sign_params)
+}
+
+/**
+ * 创建一个适用于KG的Http请求
+ * @param {*} url
+ * @param {*} options
+ * @param {*} retryNum
+ */
+export const createHttpFetch = async(url: string, options?: HttpOptions, retryNum = 0): Promise<any> => {
+  if (retryNum > 2) throw new Error('try max num')
+  let result
+  try {
+    result = await httpFetch(url, options).promise
+  } catch (err) {
+    console.log(err)
+    return createHttpFetch(url, options, ++retryNum)
+  }
+  // console.log(result.statusCode, result.body)
+  if (result.statusCode !== 200 ||
+    (
+      result.body.error_code ??
+      result.body.errcode ??
+      result.body.err_code) != 0
+  ) return createHttpFetch(url, options, ++retryNum)
+  if (result.body.data) return result.body.data
+  if (Array.isArray(result.body.info)) return result.body
+  return result.body.info
+}