fix: allow blocked chat import drafts while keeping execution validation strict

backend/wisegrade/actions.py

@@ -6,6 +6,7 @@ from pathlib import Path
 from uuid import uuid4
 
 from fastapi import HTTPException
+from pydantic import ValidationError
 from sqlalchemy import select
 
 from . import services
@@ -149,7 +150,12 @@ def prepare(db, conversation: Conversation, kind: str, payload: dict, *, teacher
         raise HTTPException(400, "整批 Excel 导出须在未限定学生项目的会话中准备")
     if kind == "import":
         from .api import ImportConfirm
-        data = ImportConfirm.model_validate(payload)
+        try:
+            data = ImportConfirm.model_validate(payload, context={
+                "allow_unselected_import_draft": not teacher_edited})
+        except ValidationError as exc:
+            messages = [error["msg"] for error in exc.errors(include_input=False, include_context=False)]
+            raise HTTPException(400, "导入资料尚未满足确认条件：" + "；".join(messages)) from exc
         payload = data.model_dump()
         require_scope(db, conversation, version_id=data.course_version_id)
         if teacher_edited and any(item.student_no == "00000" or item.name == "待确认" or item.topic == "待确认" for item in data.projects):
@@ -164,9 +170,10 @@ def prepare(db, conversation: Conversation, kind: str, payload: dict, *, teacher
             scanned.append(match)
             if match["status"] != "recognized" or match["warnings"] or any(f["status"] != "recognized" for f in match["files"]):
                 ambiguous.append(item.relative_dir)
+        unselected = any(not any(file.status != "ignored" for file in item.files) for item in data.projects)
         preview = {"course_version_id": data.course_version_id, "projects": scanned,
                    "selection": payload["projects"], "ambiguous": ambiguous,
-                   "requires_edit": bool(ambiguous) and not teacher_edited}
+                   "requires_edit": (bool(ambiguous) or unselected) and not teacher_edited}
     elif kind == "course_ingest":
         require_scope(db, conversation, version_id=payload["course_version_id"])
         preview = {"course_version_id": payload["course_version_id"], "templates":