feat: 安全增强 + 删除密码重置申请功能 + 登录提醒开关

安全增强:
- 新增 SSRF、XXE、模板注入、敏感路径探测检测规则
- security/constants.py: 添加新的威胁类型和检测模式
- security/threat_detector.py: 实现新检测逻辑

删除密码重置申请功能:
- 移除 /api/password_resets 相关API
- 删除 password_reset_requests 数据库表
- 前端移除密码重置申请页面和菜单
- 用户只能通过邮��找回密码，未绑定邮箱需联系管理员

登录提醒全局开关:
- email_service.py: 添加 login_alert_enabled 字段
- routes/api_auth.py: 检查开关状态再发送登录提醒
- EmailPage.vue: 添加新设备登录提醒开关

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

db/schema.py

@@ -239,21 +239,6 @@ def ensure_schema(conn) -> None:
         """
     )
 
-    # 密码重置申请表
-    cursor.execute(
-        """
-        CREATE TABLE IF NOT EXISTS password_reset_requests (
-            id INTEGER PRIMARY KEY AUTOINCREMENT,
-            user_id INTEGER NOT NULL,
-            new_password_hash TEXT NOT NULL,
-            status TEXT NOT NULL DEFAULT 'pending',
-            created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
-            processed_at TIMESTAMP,
-            FOREIGN KEY (user_id) REFERENCES users (id) ON DELETE CASCADE
-        )
-        """
-    )
-
     # 数据库版本表
     cursor.execute(
         """
@@ -394,9 +379,6 @@ def ensure_schema(conn) -> None:
     cursor.execute("CREATE INDEX IF NOT EXISTS idx_task_logs_created_at ON task_logs(created_at)")
     cursor.execute("CREATE INDEX IF NOT EXISTS idx_task_logs_user_date ON task_logs(user_id, created_at)")
 
-    cursor.execute("CREATE INDEX IF NOT EXISTS idx_password_reset_status ON password_reset_requests(status)")
-    cursor.execute("CREATE INDEX IF NOT EXISTS idx_password_reset_user_id ON password_reset_requests(user_id)")
-
     cursor.execute("CREATE INDEX IF NOT EXISTS idx_bug_feedbacks_user_id ON bug_feedbacks(user_id)")
     cursor.execute("CREATE INDEX IF NOT EXISTS idx_bug_feedbacks_status ON bug_feedbacks(status)")
     cursor.execute("CREATE INDEX IF NOT EXISTS idx_bug_feedbacks_created_at ON bug_feedbacks(created_at)")