AstrBot Desktop v4.26.4

Automated desktop package release.

• Source: https://github.com/AstrBotDevs/AstrBot.git
• Ref: v4.26.4
• Mode: tag-poll
• Windows package formats: nsis installer and portable zip.
• Windows portable zip uses manual replacement updates and requires WebView2 to already exist on the host.

What's Changed

• fix: mark packaged backend as desktop-managed by @zouyonghe in #146

Full Changelog: v4.26.3...v4.26.4