dsh-composer-recall: Arrow Key History for DSH Web Composer

`dsh-composer-recall` is an arrow-key input history plugin designed for the DSH Web composer to address pain points when reviewing or correcting input. It allows users to navigate the message history of the current session with the up and down arrow keys, exit with Esc and restore the draft, or leave history mode by typing directly. It supports Lexical input components and requires DeepSeek Harness 0.1.2-alpha.1 or later.