fix(students): 修复默认用户关联学生实体缺失导致/students/me 404的问题

确保默认用户有对应的学生实体，避免接口返回404错误
同时优化/students/me接口的错误处理逻辑

app/api/v1/students.py

@@ -2,7 +2,8 @@ from fastapi import APIRouter, Depends, HTTPException, Path, Body
 from pydantic import BaseModel
 from typing import Optional, Dict, Any
 from app.api.deps import require_edition_for_mode, require_role
-from app.services.student_binding import bind_user_to_student, unbind_user_from_student, get_student_by_user
+from app.services.student_binding import bind_user_to_student, unbind_user_from_student
+from app.services.dashboard import _get_student_by_user
 
 router = APIRouter(dependencies=[Depends(require_edition_for_mode())])
 
@@ -61,8 +62,13 @@ async def unbind(student_id: str = Path(..., description="学生ID"), current_us
     },
 )
 async def me(current_user: dict = Depends(require_role(1))) -> StudentOut:
-    s = await get_student_by_user(str(current_user["_id"]))
+    try:
+        s = await _get_student_by_user(current_user["_id"])
         if not s:
             raise HTTPException(status_code=404, detail="当前用户未绑定学生")
-    s["_id"] = str(s["_id"])  # 简化返回
+        s["_id"] = str(s["_id"])
         return s
+    except HTTPException as e:
+        if e.status_code == 404:
+            raise HTTPException(status_code=404, detail="当前用户未绑定学生")
+        raise e

init_db.py

@@ -594,6 +594,25 @@ async def seed_identity_data(db, mode: str):
     if user_doc:
         p = find_person("P-STU-USER")
         bindings.append({"account_id": user_doc["_id"], "person_id": p["_id"], "type": "student", "primary": True})
+        
+        # 修复：为默认用户创建关联的学生实体，防止 /students/me 404
+        # 注意：P-STU-USER 是人物，这里需要一个对应的 student 实体指向它
+        existing_stu = await db.students.find_one({"person_id": p["_id"]})
+        if not existing_stu:
+            await db.students.insert_one({
+                "student_id": "STU-USER-001",
+                "name": "默认学生USER",
+                "gender": "男",
+                "grade": "22级",
+                "major": "软件技术",
+                "class_id": "SW22-1", # 默认分到 1 班
+                "status": "在读",
+                "person_id": p["_id"],
+                "created_at": datetime.now(),
+                "updated_at": datetime.now(),
+            })
+            print("已为默认用户 user 创建关联学生实体")
+
     if manager_doc:
         p = find_person("P-TEA-001")
         bindings.append({"account_id": manager_doc["_id"], "person_id": p["_id"], "type": "teacher", "primary": True})