dsh-cache-probe: Directly measure prompt cache hit rate and response speed of channels in DSH

The DSH plugin maintained by xymy666 opens a standalone "Channel Testing" page in the Web GUI to test the cache hit rate and response speed of configured channel test prompts, using Pelican SVG to inspect model output. The three tests feature independent parameters: thinking level, payload character count, and retry rounds are adjustable. The result card includes a round-by-round table and a copyable text report. The page uses the plugin's own Host HTTP interface, without registering slash commands or writing cards to the conversation. The article provides npm and GitHub installation commands, typical usage, a default parameter table, the Host interface and security safeguards, as well as costs and known limitations.