dsh-suggested-replies: Next Reply Candidate Plugin for DSH Web

`dsh-suggested-replies` is a "suggested replies" plugin for DSH Web, designed to address the pain point where users manually craft their next message after receiving an AI response. After the AI completes its reply, it generates 2-4 candidate next-step messages (such as execution, verification, decision-making, etc.) based on recent conversation context, displayed above the input box. When a user clicks a candidate, it only fills the draft without auto-sending, ensuring human control remains intact. The core workflow of the plugin is: AI reply ends -> runs a short-text internal Agent to generate candidates -> status written to a specific domain -> frontend display. Candidate rows are displayed in a single line, with horizontal scrolling when width is insufficient; it supports deduplication and language follow. If the auxiliary model call fails or times out, the plugin generates conservative candidates and does not hide the entire row. Installation requires adding the npm package via the `dsh plugin` command.