dsh-updater-ui: Check and Update Official DSH on the DSH Settings Page

dsh-updater-ui is a web update plugin for DSH, designed to streamline the official DSH check and update process. The plugin automatically selects the update channel by identifying the installation method of the currently running process (source repository, npm global, or npx): for source-based installation, it performs a fast-forward update via `git fetch`, compares version numbers, and displays commit history; for npm-based installation, it installs the specified version from the official registry. The plugin features automatic background checks every 30 minutes, a red dot notification, and one-click update functionality, along with safety restrictions such as refusing to overwrite local unpushed commits, fixing the package name for installation, and limiting request origins. It is suitable for DSH developers who want to reduce manual judgment of installation methods; after installation, operations are performed via the "Settings → DSH Update" page. The plugin has no third-party dependencies, is licensed under the MIT license, and requires ensuring