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/types.py

@@ -0,0 +1,122 @@
+"""SDK 共享类型约定。
+
+Python 无编译期类型强制，这里的 TypedDict / Protocol 只作为迁移时的形状文档；
+运行时行为与 TS 版一致（普通 dict）。
+"""
+
+from __future__ import annotations
+
+from typing import Any, Protocol, TypedDict, runtime_checkable
+
+SOURCE_IDS = (
+    "kw",
+    "kg",
+    "tx",
+    "wy",
+    "mg",
+    "bd",
+    "joox",
+    "bili",
+    "5sing",
+    "apple",
+    "xm",
+    "me",
+    "qt",
+    "lr",
+)
+
+QUALITIES = ("64k", "128k", "320k", "flac", "flac24bit")
+
+
+class SongType(TypedDict, total=False):
+    type: str
+    size: str
+
+
+class QualityInfo(TypedDict, total=False):
+    size: str
+
+
+class SongInfo(TypedDict, total=False):
+    songmid: str
+    hash: str
+    copyrightId: str
+    songStringId: str
+    albumId: str
+    name: str | None
+    singer: str
+    source: str
+    interval: str | int
+    albumName: str
+    img: str | None
+    lrc: str | None
+    otherSource: str | None
+    types: list[SongType]
+    _types: dict[str, QualityInfo]
+    typeUrl: dict[str, str]
+
+
+class MusicUrlResult(TypedDict, total=False):
+    type: str
+    url: str
+    via: str
+    encrypted: bool
+    fileKey: str
+
+
+class LyricInfo(TypedDict, total=False):
+    lyric: str
+    tlyric: str
+    rlyric: str
+    yrc: str
+
+
+class SearchResult(TypedDict, total=False):
+    list: list[dict[str, Any]]
+    allPage: int
+    total: int
+    limit: int
+    source: str
+
+
+@runtime_checkable
+class MusicSearchModule(Protocol):
+    async def search(self, keyword: str, page: int = 1, limit: int = 20, retry_num: int = 0) -> SearchResult: ...
+
+
+async def search(keyword: str, page: int = 1, limit: int = 20) -> SearchResult:
+    """占位，供类型检查引用。"""
+    raise NotImplementedError
+
+
+class PlatformModule(Protocol):
+    """平台模块契约（对应原 sdk/types.ts 的 PlatformModule）。
+
+    musicSearch / leaderboard / songList / hotSearch / singer / album / playlist /
+    parse / userPlaylist 为子模块对象；get_music_url / get_lyric / get_pic 为可等待方法。
+    各平台按能力自由实现，缺省表示不支持（/sources 的能力位据此判断）。
+    """
+
+    musicSearch: Any
+    leaderboard: Any
+    songList: Any
+    hotSearch: Any
+    singer: Any
+    album: Any
+    playlist: Any
+    parse: Any
+    userPlaylist: Any
+
+
+def cap(obj: Any, path: str | None = None) -> Any:
+    """按 `album.searchAlbum` 形式的嵌套路径取能力位（None 表示不支持）。"""
+    if obj is None:
+        return None
+    if not path:
+        return obj
+    cur = obj
+    for key in path.split("."):
+        cur = getattr(cur, key, None) if not isinstance(cur, dict) else cur.get(key)
+        if cur is None:
+            return None
+    return cur