feat: 方案待定制可编辑+通知去定制按钮+权限修复

- 会员等待中可修改健康需求，修改后通知老师
- 通知里方案请求显示"去定制"按钮跳转用户管理
- 后端: 方案owner可更新health_desc，teacher可改title/status

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

backend/main.py

@@ -1659,12 +1659,21 @@ def update_oil_plan(plan_id: int, body: dict, user=Depends(get_current_user)):
     if not plan:
         conn.close()
         raise HTTPException(404, "方案不存在")
-    if plan["teacher_id"] != user["id"] and user["role"] != "admin":
+    is_teacher = plan["teacher_id"] == user["id"] or user["role"] == "admin"
+    is_owner = plan["user_id"] == user["id"]
+    if not is_teacher and not is_owner:
         conn.close()
         raise HTTPException(403, "无权操作")
-    if "title" in body:
+    if "health_desc" in body and is_owner:
+        conn.execute("UPDATE oil_plans SET health_desc = ? WHERE id = ?", (body["health_desc"], plan_id))
+        who = user.get("display_name") or user["username"]
+        conn.execute(
+            "INSERT INTO notifications (target_role, title, body, target_user_id) VALUES (?, ?, ?, ?)",
+            ("admin", "📋 方案需求已更新", f"{who} 更新了健康需求：{body['health_desc'][:50]}", plan["teacher_id"])
+        )
+    if "title" in body and is_teacher:
         conn.execute("UPDATE oil_plans SET title = ? WHERE id = ?", (body["title"], plan_id))
-    if "status" in body:
+    if "status" in body and is_teacher:
         old_status = plan["status"]
         conn.execute("UPDATE oil_plans SET status = ? WHERE id = ?", (body["status"], plan_id))
         if body["status"] == "active" and old_status != "active":