dsh-dl-server: Persistent Download Queue for DSH

DLS (dsh-dl-server) is a global, session-aware, persistent download queue provided by Jestions-dev for DeepSeek Harness. It addresses issues such as task loss when sessions end, lack of pause and resume functionality for queues, and state not being preserved after restarts. Through seven tools including `download_enqueue`, it enables immediate return upon enqueuing, cross-session visibility, and modification only by the initiating session. It supports optional aria2 segmented transfers and requires DSH version 0.2.1-rc.5 or higher. The installation command is `dsh plugin add dsh-dl-server` or by adding the same-named plugin via the UI.