fix(dufe): 修复 base64 %3D 容错与 commit 判定 fail-open

ginkgo_sign_in.py:
- 顶部新增 import urllib.parse
- _b64_decode: 先 urllib.parse.unquote 再做 空格->+ 替换
  （iOS 快捷指令会把 base64 的 = 编码成 %3D，旧实现直接 binascii.Error；
    顺序必须是 unquote 在 空格->+ 之前，否则 %20 会被误当成被 form-urlencoded 吃掉的 +）
- commit 判定改为 fail-closed：要求 commit_info 是 dict 且 success is True，
  否则一律返回 msg="sign-in failed: <原因>"；
  do_commit=false 时不检查 commit 字段，msg 仍为 "ok"
- reason 取值修正：非 dict 真值（字符串/数字）不再触发 AttributeError 500，
  统一回落到 "no commit result returned"
- parse_course_url 报错文案改为
  "URL is not a sign-in page (missing /signin/<signInId>/<type>): <url>"

文档：README 版本要点与 docs/部署与运维.md 变更记录同步

source/dufe/ginkgostu_sign_in/ginkgo_sign_in.py

@@ -15,6 +15,7 @@ import json
 import logging
 import re
 import sys
+import urllib.parse
 import uuid
 
 try:
@@ -250,7 +251,8 @@ def parse_course_url(url):
         r"/course/detail/(?P<courseId>\d+)/(?P<batchNo>[^/]+)/"
         r"(?P<weekTimeId>\d+)/signin/(?P<signInId>\d+)/(?P<type>\d+)", url)
     if not m:
-        raise ValueError("Cannot parse course URL: %s" % url)
+        raise ValueError(
+            "URL is not a sign-in page (missing /signin/<signInId>/<type>): %s" % url)
     return m.groupdict()
 
 
@@ -462,13 +464,18 @@ def _b64_decode(value, field):
     """
     Decode a base64 query/form parameter tolerantly.
 
-    Handles:
-      * '+' turned into ' ' by application/x-www-form-urlencoded
-      * trailing newline from `base64` CLI without -w0
-      * both standard (+/) and urlsafe (-_) alphabets
+    Handles, in order:
+      * '%3D' / '%2B' / '%20' -- iOS Shortcuts and some HTTP clients
+        URL-encode the base64 payload (notably the trailing '='), so we
+        percent-decode first.
+      * '+' turned into ' ' by application/x-www-form-urlencoded.
+      * trailing newline from `base64` CLI without -w0.
+      * both standard (+/) and urlsafe (-_) alphabets.
     """
-    v = (value or "").strip()
-    v = v.replace(" ", "+").replace("\r", "").replace("\n", "")
+    v = urllib.parse.unquote(value or "")
+    v = v.strip()
+    v = v.replace(" ", "+")
+    v = v.replace("\r", "").replace("\n", "")
     if not v:
         raise ValueError("Empty base64 for '%s'" % field)
     try:
@@ -503,15 +510,20 @@ def ginkgostu_sign_in():
     log.info("query start user=%s commit=%s", username[:2] + "***", do_commit)
     try:
         data = fetch_sign_in_info(username, password, course_url, do_commit=do_commit)
-        commit_info = data.get("commit") or {}
-        if do_commit and not commit_info.get("success", True):
-            log.warning("sign-in commit failed user=%s reason=%s",
-                        username[:2] + "***", commit_info.get("message"))
-            return jsonify({
-                "code": 200,
-                "msg": "sign-in failed: %s" % commit_info.get("message", "unknown reason"),
-                "data": data,
-            })
+
+        if do_commit:
+            # Fail-closed: only an explicit success=true counts as signed in.
+            commit_info = data.get("commit")
+            if not isinstance(commit_info, dict) or commit_info.get("success") is not True:
+                reason = (commit_info.get("message") if isinstance(commit_info, dict) else None) or "no commit result returned"
+                log.warning("sign-in commit failed user=%s reason=%s",
+                            username[:2] + "***", reason)
+                return jsonify({
+                    "code": 200,
+                    "msg": "sign-in failed: %s" % reason,
+                    "data": data,
+                })
+
         log.info("query ok user=%s code=%s", username[:2] + "***", data.get("signInCode"))
         return jsonify({"code": 200, "msg": "ok", "data": data})
     except AuthError as e: