feat(desktop): let the pet perch on the status bar and profile rail

Tag both bars with data-slots; the roam loop stands on the status bar's top edge (not over it) and treats the profile rail as a climbable ledge.

apps/desktop/src/app/chat/sidebar/profile-switcher.tsx

@@ -200,7 +200,7 @@ export function ProfileRail() {
   }, [createRequest])
 
   return (
-    <div aria-label="Profiles" className="flex items-center gap-0.5" role="tablist">
+    <div aria-label="Profiles" className="flex items-center gap-0.5" data-slot="profile-rail" role="tablist">
       {/* One button toggles default ↔ all: home face when scoped to a profile,
           layers face when showing everything. Pinned left like Manage is right.
           Hidden until a second profile exists. */}

apps/desktop/src/app/shell/statusbar-controls.tsx

@@ -64,6 +64,7 @@ export function StatusbarControls({ className, leftItems = [], items = [], ...pr
         'flex h-5 shrink-0 items-stretch justify-between gap-2 border-t border-(--ui-stroke-tertiary) bg-(--ui-sidebar-surface-background) px-1 py-0 text-(--ui-text-tertiary) [-webkit-app-region:no-drag]',
         className
       )}
+      data-slot="statusbar"
       {...props}
     >
       {/* `overflow-x-clip` (not `overflow-x-auto`) so a wide status item — for