omdsh-sidepanel: File Panel and Terminal in Work Mode

`omdsh-sidepanel` is a lightweight plugin designed for DeepSeek Harness Work mode, intended to supplement the missing file management and terminal execution capabilities. It is not displayed in Chat mode and provides file tree browsing, preview, and shell access through a right-side file panel and a bottom terminal panel. Users can control the panels via toggles or keyboard shortcuts, with support for resizing by dragging, resetting, and copying paths. Once installed, the panels take effect only in Work mode, focusing on file viewing and command execution, making it a practical tool for developers to improve efficiency when using Harness.