fix(ddic): create 命令消费 JSON description（--description 优先→JSON→回退名）；upload testclasses XML 包裹通道（S4T 三轮实证）；SKILL 错误速查表 +4 条 NW740 实证（ADT 创建不持久化文本/classes 激活空响应/unknown comments/STRG+comptype 陷阱）

assets/sapcli/client/_source.py

@@ -42,6 +42,7 @@ class SourceMixin:
         source: str,
         lock_handle: str,
         corr_nr: str | None = None,
+        content_type: str | None = None,
     ) -> bool:
         params: dict[str, str] = {}
         if lock_handle:
@@ -49,8 +50,9 @@ class SourceMixin:
         if corr_nr:
             params["corrNr"] = corr_nr
         url = f"{self.host}{src_uri}"
-        hdrs = self._headers("text/plain; charset=utf-8")
-        logger.info("SET SOURCE: PUT %s (%d chars)", url, len(source))
+        ct = content_type or "text/plain; charset=utf-8"
+        hdrs = self._headers(ct)
+        logger.info("SET SOURCE: PUT %s (%d chars, ct=%s)", url, len(source), ct)
         resp = self.session.put(
             url, headers=hdrs, params=params, data=source.encode("utf-8")
         )