feat(ship): clarify delivery stop semantics

skills/ship/scripts/validate_ship.py

@@ -13,6 +13,7 @@ from ship_lib import (
     DELIVERY_STATE,
     KIND,
     SHIP_STATUS,
+    STOP_AT,
     SOURCE_KIND,
     TASK_STATUS,
     check_ship_id,
@@ -77,6 +78,17 @@ def validate_ship_dir(ship_dir: Path) -> list[str]:
     if not isinstance(data.get("title"), str) or not str(data.get("title")).strip():
         _issue(issues, "title 不能为空")
 
+    for path, value in (
+        ("stopAt", data.get("stopAt")),
+        ("delivery.stopAt", (data.get("delivery") or {}).get("stopAt")
+         if isinstance(data.get("delivery"), dict) else None),
+    ):
+        if value not in (None, "") and value not in STOP_AT:
+            _issue(
+                issues,
+                f"{path} 无效: {value!r}（{', '.join(sorted(STOP_AT))}）",
+            )
+
     source = data.get("source")
     if source is not None:
         src = _mapping(source, "source", issues)