fix(client): re-inset the right-sidebar tab after dockkit's pane padding removal

The dockkit pane body no longer pads itself and leaves each tab its own insets, so the Context tab sat flush against all four panel edges. Give the sidebar-scoped root a 12px frame instead of zero, matching the harness's own body inset; the conversation tab and the /context modal are unaffected.

src/client/styles/base.css

@@ -8,16 +8,17 @@
  */
 .lc-root { padding: 16px 20px 32px; overflow-y: auto; height: 100%; box-sizing: border-box; color: var(--dsw-alias-label-primary); font-size: 13px; }
 /*
- Right Sidebar panel (dsh 0.1.5-alpha.2+): the dockkit pane body already pads (12px)
- and scrolls, and its `.pane` clips overflow — so the tab root drops its own
- scroller and inset and lets the pane own both. One scroller per panel, no
- double padding on a narrow pane. Scoped by the panel's own markers, which
- exist only inside the right column (the open panel and the float host that
- carries a tab dragged out of it); the conversation tab and the /context modal
- are unaffected.
+ Right Sidebar panel (dsh 0.1.5-alpha.2+): the dockkit pane body scrolls and
+ its `.pane` clips overflow — so the tab root drops its own scroller and lets
+ the pane own both. The body draws NO padding of its own (dockkit leaves each
+ tab its own insets), so the root keeps a 12px frame on all four sides — the
+ harness's own body inset — instead of the wide shared chrome. Scoped by the
+ panel's own markers, which exist only inside the right column (the open panel
+ and the float host that carries a tab dragged out of it); the conversation tab
+ and the /context modal are unaffected.
  */
 [data-sidebar-right-open] .lc-root,
-[data-sidebar-right-float-host] .lc-root { height: auto; overflow: visible; padding: 0; }
+[data-sidebar-right-float-host] .lc-root { height: auto; overflow: visible; padding: 12px; }
 /*
  Border roles: l2 (0.1 black ≈ #E5E5E5 on white) draws the VISIBLE edges —
  cards and controls, matching dsh's own Button/Input chrome; l1 stays for