dsh-quote-reply liuhaolong16

Quote reply layer for DeepSeek Harness: quote a passage into an editable tray above the composer; it rides into the next turn as model context (never into the message body) and shows as an expandable row under that turn. 引用回复层：选中一段进引用行，随下一回合作为上下文注入模型（不进消息正文），回合尾部显示可展开的引用(N)。