dsh-ui-personalization: Customizing Sidebar and Balance Display

DeepSeek Harness’s default sidebar feature provides the foundation. The `dsh-ui-personalization` plugin achieves highly customizable UI by taking over UI slots. Users can replace the bottom system account row, customize the avatar, nickname, and balance, or hide the top brand mark. Configuration is centrally managed on the “Personalization” page in the settings panel. Note that the logout function will be disabled, and version compatibility may change with client upgrades, requiring manual updates to hardcoded version numbers.