feat(auth): print a scannable ASCII QR in the terminal

WSL and --no-browser never showed the PNG, and placeholder Chinese cookies crashed urllib latin-1 headers before the code was issued.

reaction_board/bilibili/auth.py

@@ -45,12 +45,30 @@ def strip_identity(cookie: str) -> str:
     return "; ".join(kept)
 
 
+def _is_latin1(value: str) -> bool:
+    try:
+        value.encode("latin-1")
+    except UnicodeEncodeError:
+        return False
+    return True
+
+
+def cookie_header(cookie: str, *, auth: bool = False) -> str:
+    """生成可放入 HTTP 头的 Cookie。占位中文、缺 ``=`` 的片段和非 latin-1 字段都会丢掉。"""
+    source = cookie if auth else strip_identity(cookie)
+    return "; ".join(
+        f"{key}={value}"
+        for key, value in parse_cookie(source)
+        if _is_latin1(key) and _is_latin1(value)
+    )
+
+
 def make_headers(cfg: dict, auth: bool = False, *, referer: str | None = None) -> dict[str, str]:
     """构造与 ``data/raw-request.txt`` 对齐的 B 站 Web 请求头。"""
     return {
         "accept": "*/*",
         "accept-language": "zh-CN,zh;q=0.9,en-US;q=0.8,en;q=0.7",
-        "cookie": cfg["cookie"] if auth else strip_identity(cfg["cookie"]),
+        "cookie": cookie_header(str(cfg.get("cookie") or ""), auth=auth),
         "dnt": "1",
         "origin": "https://space.bilibili.com",
         "priority": "u=1, i",