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/kg/krc_decode.py

@@ -0,0 +1,102 @@
+"""酷狗 KRC 歌词解密（对应 sdk/kg/krcDecode.ts）。
+
+密文是 base64 → 去掉 4 字节头 → 与 16 字节固定 key 循环异或 → zlib inflate。
+解密后是带 `[start,duration]` 行级标签与 `<offset,duration,0>` 字级标签的 KRC 文本，
+另外 `[language:<base64>]` 行里藏着 base64(JSON) 的逐行翻译，需按行号拼回 LRC。
+"""
+
+from __future__ import annotations
+
+import base64
+import json
+import re
+import zlib
+from typing import Any
+
+from app.sdk.common.utils import decode_name
+
+ENC_KEY = bytes([0x40, 0x47, 0x61, 0x77, 0x5E, 0x32, 0x74, 0x47, 0x51, 0x36, 0x31, 0x2D, 0xCE, 0xD2, 0x6E, 0x69])
+
+_HEAD_EXP = re.compile(r"^.*\[id:\$\w+\]\n")
+_TRANS_EXP = re.compile(r"\[language:([\w=\\/+]+)\]")
+_TRANS_LINE_EXP = re.compile(r"\[language:[\w=\\/+]+\]\n")
+_LINE_EXP = re.compile(r"\[((\d+),\d+)\].*")
+_WORD_TAG_EXP = re.compile(r"<(\d+,\d+),\d+>")
+_PLAIN_TAG_EXP = re.compile(r"<\d+,\d+>")
+
+
+def _xor_decode(data: str) -> str:
+    if not data:
+        return ""
+    buf = bytearray(base64.b64decode(data)[4:])
+    for i in range(len(buf)):
+        buf[i] ^= ENC_KEY[i % 16]
+    return zlib.decompress(bytes(buf)).decode("utf-8", errors="replace")
+
+
+def _format_time(ms: int) -> str:
+    """毫秒 → `mm:ss.ms`（毫秒段与原文一致不补零）。"""
+    minutes, rem = divmod(ms, 60000)
+    return f"{minutes:02d}:{rem // 1000:02d}.{ms % 1000}"
+
+
+def _lrc_line(value: Any) -> str:
+    """rlyric/tlyric 的单项是字符串数组（逐字），字符串形态也容忍。"""
+    if isinstance(value, list):
+        return "".join(str(item) for item in value)
+    return "" if value is None else str(value)
+
+
+def parse_lyric(text: str) -> dict[str, str]:
+    text = text.replace("\r", "")
+    if _HEAD_EXP.match(text):
+        text = _HEAD_EXP.sub("", text, count=1)
+
+    rlyric: list[Any] | None = None
+    tlyric: list[Any] | None = None
+    trans = _TRANS_EXP.search(text)
+    if trans:
+        text = _TRANS_LINE_EXP.sub("", text, count=1)
+        try:
+            payload = json.loads(base64.b64decode(trans.group(1)).decode("utf-8", errors="replace"))
+        except ValueError:
+            payload = {}
+        for item in payload.get("content") or []:
+            if item.get("type") == 0:
+                rlyric = item.get("lyricContent")
+            elif item.get("type") == 1:
+                tlyric = item.get("lyricContent")
+
+    index = 0
+
+    def repl(match: re.Match[str]) -> str:
+        nonlocal index
+        line_match = _LINE_EXP.match(match.group(0))
+        time_ms = int(line_match.group(2)) if line_match else 0
+        stamp = _format_time(time_ms)
+        if rlyric is not None:
+            rlyric[index] = f"[{stamp}]{_lrc_line(rlyric[index]) if index < len(rlyric) else ''}"
+        if tlyric is not None:
+            tlyric[index] = f"[{stamp}]{_lrc_line(tlyric[index]) if index < len(tlyric) else ''}"
+        index += 1
+        return match.group(0).replace(match.group(1), stamp, 1)
+
+    yrc = re.sub(r"\[((\d+),\d+)\].*", repl, text)
+    rlyric_text = "\n".join(str(item) for item in rlyric) if rlyric else ""
+    tlyric_text = "\n".join(str(item) for item in tlyric) if tlyric else ""
+    yrc = _WORD_TAG_EXP.sub(r"<\1>", yrc)
+    yrc = decode_name(yrc)
+    lyric = _PLAIN_TAG_EXP.sub("", yrc)
+    return {
+        "lyric": lyric,
+        "tlyric": decode_name(tlyric_text),
+        "rlyric": decode_name(rlyric_text),
+        "yrc": yrc,
+    }
+
+
+async def decode_krc(data: str) -> dict[str, str]:
+    return parse_lyric(_xor_decode(data))
+
+
+__all__ = ["decode_krc", "parse_lyric"]