dsh-client-ui-details-host

In the DSH AppFrame layout the third column (the details panel) is the natural home for feature-plugin surfaces that need richer interaction than a simple drawer. Yet developers have long lacked a stable host layer to manage panel lifecycle, column chrome, and session navigation. dsh-client-ui-details-host fills that gap as a pure-web UI infrastructure plugin with no Electron, Node, or desktop runtime dependency, running identically in DeepSeek Harness Desktop and any standard DSH Web host.

At its core the plugin injects a ctx.shellDetails controller (API v2) into the host, exposing open, close, back, toggle, registerSurface, getSnapshot, and subscribe. Column chrome (resize handle, close control, header action buttons) and the graceful hand-back to the upstream DetailsPanel are handled out of the box. A feature plugin only needs to call ctx.shellDetails.open with a registered surface id to project its UI into the third column. Session navigation uses an in-memory bounded back stack with dedupe and optional replace semantics, so switching between registered surfaces keeps the host mounted without tearing down the column.

This plugin is aimed at DSH feature-plugin authors who want to build panel-style experiences in the AppFrame details column. Whether the surface is a document viewer, a configuration editor, or a live data panel, the details-host package provides the column chrome, lifecycle management, and slot-based registration needed to ship a polished third-column UI without reinventing the infrastructure. It is deliberately scoped to a single active surface at a time with memory-only session state, making it lightweight and predictable for Web-first compositions.