新增作文区与 AI 解读开关，修复 CSV 导出。

系统设置可关闭成绩复盘 AI；学生详情增加作文区（OCR/手动题目、方案与范文、历史与 MD 下载）；导出改用 UTF-8 文件名响应。

Co-authored-by: Cursor <cursoragent@cursor.com>

backend/app/routers/export.py

@@ -1,9 +1,10 @@
 import csv
 import io
 import uuid
+from urllib.parse import quote
 
 from fastapi import APIRouter, Depends
-from fastapi.responses import StreamingResponse
+from fastapi.responses import Response
 from sqlalchemy.orm import Session, joinedload
 
 from app.core.database import get_db
@@ -34,10 +35,11 @@ def export_scores_csv(
     writer.writerow(["考试日期", "考试类型", "标题", "科目", "总分", "得分", "占比"])
     type_map = {"weekly": "周考", "monthly": "月考", "final": "期末"}
     for exam in exams:
+        exam_type = exam.exam_type.value if hasattr(exam.exam_type, "value") else str(exam.exam_type)
         for score in exam.scores:
             writer.writerow([
                 exam.exam_date.isoformat(),
-                type_map.get(exam.exam_type.value, exam.exam_type.value),
+                type_map.get(exam_type, exam_type),
                 exam.title or "",
                 score.subject.name if score.subject else "",
                 float(score.total_score),
@@ -45,10 +47,13 @@ def export_scores_csv(
                 f"{float(score.ratio) * 100:.2f}%",
             ])
 
-    output.seek(0)
+    content = output.getvalue().encode("utf-8-sig")
     filename = f"{student.name}_scores.csv"
-    return StreamingResponse(
-        iter([output.getvalue().encode("utf-8-sig")]),
-        media_type="text/csv",
-        headers={"Content-Disposition": f'attachment; filename="{filename}"'},
+    encoded = quote(filename)
+    return Response(
+        content=content,
+        media_type="text/csv; charset=utf-8",
+        headers={
+            "Content-Disposition": f'attachment; filename="scores.csv"; filename*=UTF-8\'\'{encoded}'
+        },
     )