dsh-table-copy: Add a hover toolbar to Markdown tables, one-click copy as Markdown or PNG

dsh-table-copy is a client-side plugin maintained by jiongboy that adds a hover toolbar to all Markdown-rendered tables in DeepSeek Harness Web. The left button copies the table as PNG to the clipboard (falling back to download if the browser blocks it), while the right button copies it as Markdown. The plugin operates entirely on the client side with no network requests or file system access, solely manipulating the clipboard, and supports both light and dark themes. This article documents the installation command, usage workflow, implementation details of MutationObserver and captions, known limitations (must use a data: URL, screenshots are taken based on rendered width, links are unclickable, and it only decorates Markdown tables), and development check commands.