feat: pick the focus and the allowed paths from a directory listing

Both scope controls were free-text boxes, and the vocabulary they asked the user
for is paths relative to the session folder. "Which folder is `../shared`" is the
one question a text box cannot answer, so the panel now shows the Host's own
directory: the `uiWorkspace.listDirectory` primitive the workspace picker's
browser drives, one level of child folders, a breadcrumb trail, and a
hidden-entries toggle. The path field stays editable inside the picker, because
the Host lists folders and an extra may legitimately name a file.

Picks are stored in the form that keeps their meaning. A folder at
`/work/root/src/shared` is declared `src/shared` when the session started in
`/work/root`, and `../shared` going up; only a path with nothing shared — another
drive, another tree — stays absolute. The Focus row shows that declared form,
with the resolved path in its title, which is what the agent will see.

`Set` is gone with the box it committed: the panel writes on pick, as every other
control here already did. `Clear` stays, because empty means the session folder —
the schema's own default rather than an override naming the same place.

The card was 380px wide and grew without bound, a single column of prose taller
than the viewport. It is 760px now, with a two-column grid that `auto-fit`
collapses to one on a narrow card, the reference prose folded into `<details>`,
and a scroll-bounded body. `Modal` sizes its own card from a hashed class in the
primitives' stylesheet, so this bundle installs one small stylesheet of its own
and outranks that rule with a doubled class selector — no `!important`, and
nothing reaching into a class name it does not own.

Two fixes came with it. The footer's "Deployment mode:" line read a slot prop
that never carried the mode, so it said "ask" in every deployment; it reads the
settings document now. And `uiWorkspace` is resolved with `ctx.get` at the call
rather than injected, because the panel is still the only way to declare scope in
a deployment with no directory browser: it keeps the panel and says what it
cannot do, instead of losing the button.

package.json

@@ -50,7 +50,8 @@
       "inject": [
         "@deepseek-ai/dsh-client-ui-settings",
         "@deepseek-ai/dsh-client-ui-plugin-manager",
-        "@deepseek-ai/dsh-client-ui-conversation"
+        "@deepseek-ai/dsh-client-ui-conversation",
+        "@deepseek-ai/dsh-client-ui-workspace"
       ]
     }
   },