dsh-client-ui-gpt-helper: ChatGPT-Style Model Control for DSH Web

`dsh-client-ui-gpt-helper` is a plugin designed specifically for the DeepSeek Harness web client, aiming to provide an interaction experience closer to that of the desktop version. By replacing the default model selection control, it adds a grouped model list, a thinking-level slider with particle trail animations, lightning mode toggling, and mode locking. Users can use arrow keys or dragging to adjust thinking depth, hold an icon to lock the mode, and customize color schemes with keyboard shortcuts. The plugin reuses the data layer to ensure synchronization, supports installation by package name or local path, and is suitable for users who seek fine-grained control and visual feedback.