fix(console-ui-next): fix login page loop and header when auth disabled

[Sunrisea]

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What is the purpose of the change

fix login page loop and header when auth disabled

Brief changelog

• AuthGuard now bypasses token check when authEnabled=false or loginPageEnabled=false, breaking the redirect loop between AuthGuard and login page
• Header hides user menu (avatar, change password, logout) when auth is disabled

Verifying this change

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[github-actions]

Thanks for your this PR. 🙏
Please check again for your PR changes whether contains any usage/api/configuration change such as Add new API , Add new configuration, Change default value of configuration.
If so, please add or update documents(markdown type) in docs/next/ for repository nacos-group/nacos-group.github.io

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感谢您提交的PR。 🙏
请再次查看您的PR内容，确认是否包含任何使用方式/API/配置参数的变更，如：新增API、新增配置参数、修改默认配置等操作。
如果是，请确保在提交之前，在仓库nacos-group/nacos-group.github.io中的docs/next/目录下添加或更新文档（markdown格式）。

[cxhello]

@CH3CHO FYI this PR also fixes #14926 (reported against v3.2.0, which was released before this fix landed). The reproduction in that issue — setting NACOS_CORE_AUTH_CONSOLE_ENABLED=false with NACOS_CONSOLE_UI_DEFAULT=next — hits exactly the AuthGuard ↔ LoginPage redirect loop fixed here. The issue is currently locked (anti-spam), so leaving the note here instead.

[CH3CHO]

@CH3CHO FYI this PR also fixes #14926 (reported against v3.2.0, which was released before this fix landed). The reproduction in that issue — setting NACOS_CORE_AUTH_CONSOLE_ENABLED=false with NACOS_CONSOLE_UI_DEFAULT=next — hits exactly the AuthGuard ↔ LoginPage redirect loop fixed here. The issue is currently locked (anti-spam), so leaving the note here instead.

Thanks. It works properly with image nacos/nacos-server:v3.2.1-2026.04.03. I will close that issue later.