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/migrations.py

@@ -78,6 +78,9 @@ def migrate_database(conn, target_version: int) -> None:
     if current_version < 14:
         _migrate_to_v14(conn)
         current_version = 14
+    if current_version < 15:
+        _migrate_to_v15(conn)
+        current_version = 15
 
     if current_version != int(target_version):
         set_current_version(conn, int(target_version))
@@ -639,3 +642,33 @@ def _migrate_to_v14(conn):
     cursor.execute("CREATE INDEX IF NOT EXISTS idx_user_blacklist_expires ON user_blacklist(expires_at)")
 
     conn.commit()
+
+
+def _migrate_to_v15(conn):
+    """迁移到版本15 - 邮件设置：新设备登录提醒全局开关"""
+    cursor = conn.cursor()
+
+    cursor.execute("SELECT name FROM sqlite_master WHERE type='table' AND name='email_settings'")
+    if not cursor.fetchone():
+        # 邮件表由 email_service.init_email_tables 创建；此处仅做增量字段迁移
+        return
+
+    cursor.execute("PRAGMA table_info(email_settings)")
+    columns = [col[1] for col in cursor.fetchall()]
+
+    changed = False
+    if "login_alert_enabled" not in columns:
+        cursor.execute("ALTER TABLE email_settings ADD COLUMN login_alert_enabled INTEGER DEFAULT 1")
+        print("  ✓ 添加 email_settings.login_alert_enabled 字段")
+        changed = True
+
+    try:
+        cursor.execute("UPDATE email_settings SET login_alert_enabled = 1 WHERE login_alert_enabled IS NULL")
+        if cursor.rowcount:
+            changed = True
+    except sqlite3.OperationalError:
+        # 列不存在等情况由上方迁移兜底；不阻断主流程
+        pass
+
+    if changed:
+        conn.commit()