dsh-sidechat v0.4.6

Prebuilt DSH side-chat plugin with native conversation rendering, selection annotations and handback. Based on gyixuan's dsh-sidenote: https://github.com/g-yixuan/dsh-sidenote . Original MIT copyright and license preserved. Independently maintained derivative, not an official upstream release. Supports declared DSH versions including 0.2.1-alpha.4; rendering varies by host and theme.