DSH Background: Adding Persistent Background Settings to DSH Web

The `awesome-dsh-background-plugin` maintained by leavestring (current version 0.1.9, MIT license) is a DSH web background settings plugin designed to provide persistent background customization functionality. This plugin allows users to upload images (JPG/PNG/WEBP/GIF) or switch between three preset ambiences: Aurora, Ember, and Rice Paper. Images are locally compressed to WEBP in the browser, with no data sent to third parties, ensuring privacy. Core features include fine-tuning across five dimensions (presence, overlay, soft focus, fit, focal point), real-time preview, persistent settings (retained across restarts), as well as bilingual and multi-theme support. Installation requires Node.js ≥ 18 and pnpm, and can be done via a one-click script or manual commands, with `ui-background` added to the whitelist.