feat: 完成多用户系统（登录/注册界面 + 用户隔离）

fix_migrate.py

@@ -0,0 +1,12 @@
+#!/usr/bin/env python3
+import os, sys
+sys.path.insert(0, '/root/.openclaw/workspace/diary-system/backend')
+os.environ['DJANGO_SETTINGS_MODULE'] = 'diary_system.settings'
+
+# 先删除有问题的迁移
+import subprocess
+subprocess.run(['rm', '-f', 'diary/migrations/0008_*.py'], cwd='/root/.openclaw/workspace/diary-system/backend')
+
+from django.core.management import execute_from_command_line
+sys.argv = ['manage.py', 'migrate']
+execute_from_command_line(sys.argv)