DFY DSH Appearance

Adds an 外观 page to the Harness settings sidebar. It preserves every visible Assistant text output and collapses the context/reasoning/tool segment immediately before that output behind its own disclosure. It also adjusts the chat font size and line-height ratio without changing the sidebar, settings UI, editor, or persisted transcript.

The process-group adapter uses the public conversation.chat.turnTail slot and the stable data-chat-flow-kind attributes emitted by DSH rc.8. It never edits conversation data; disabling or unloading the plugin removes every DOM marker. Media tool rows belong to the same per-output segment, so screenshots and visual analysis collapse with the process that produced the following text and return in their original position when that segment is expanded.