feat(python): 完成 Python 全量迁移——剩余平台、登录通道与公共层修复

- 新增 5sing/apple/xm/me/qt/lr 平台包与取流实现（含 xm-sign、MissEvan 签名、蜻蜓 HMAC、Apple developer token）
- 新增 wy/kg/tx/lr 登录：扫码、手机号、账密（kg 20028 风控指纹）、cookie 绑定、kg/tx 续期
- request 层：保留多值 Set-Cookie；JSON body 紧凑化（修复 kg 网关验签）；直连不经系统代理（对齐 Node）
- 登录路由统一 Body(embed=True)，修复扫码轮询 422；lifespan 接入登录续期调度
- ruff/format/pyright 全绿；14 平台真实联网与 HTTP 路由验证通过

app/sdk/platforms/bd/music_search.py

@@ -0,0 +1,41 @@
+"""千千音乐搜索（对应 sdk/bd/musicSearch.ts）。
+
+`/v1/search?word=&type=1&pageNo=&pageSize=`，appid + 签名。
+响应 `data.typeTrack[]`：TSID/title/albumTitle/albumAssetCode/pic/duration/artist/rateFileInfo/isVip。
+
+注：上游会跳过 isVip != 0 的曲目（VIP 无法匿名取流）；本实现保留并标记 payPlay，
+以便聚合搜索/顺播时仍能展示（取流失败会返回明确错误，路由可走兜底链路）。
+"""
+
+from __future__ import annotations
+
+import math
+from typing import Any
+
+from app.sdk.platforms.bd.util import APP_ID, api_get, api_ok, error_text, map_track, to_int, to_number
+
+
+async def search(keyword: str, page: int = 1, limit: int = 20, retry_num: int = 0) -> dict[str, Any]:
+    word = str(keyword if keyword is not None else "").strip()
+    if not word:
+        return {"list": [], "allPage": 1, "total": 0, "limit": limit, "source": "bd"}
+
+    body = await api_get(
+        "/v1/search",
+        {"word": word, "type": "1", "pageNo": str(page), "pageSize": str(limit), "appid": APP_ID},
+    )
+    # 23001 = 服务端不认该搜索类型/关键词，与原文一致：按空结果处理而不是报错
+    if not api_ok(body) and to_number(body.get("errno") if isinstance(body, dict) else None) != 23001:
+        raise RuntimeError(error_text(body, "千千搜索失败"))
+
+    data = (body.get("data") if isinstance(body, dict) else None) or {}
+    tracks = data.get("typeTrack") if isinstance(data, dict) else None
+    raw = tracks if isinstance(tracks, list) else []
+    total = to_int(data.get("total") if isinstance(data, dict) else None, len(raw))
+    have_more = to_number(data.get("haveMore") if isinstance(data, dict) else None) == 1
+
+    songs = [song for song in (map_track(item) for item in raw) if song["songmid"]]
+    page_size = max(1, limit)
+    all_page = page + 1 if have_more else max(page, math.ceil(total / page_size) or 1)
+
+    return {"list": songs, "allPage": all_page, "total": total, "limit": limit, "source": "bd"}