test(showcase): exercise the spec bare-string sort form on a real list view

The spec/renderer shape-mismatch audit (objectui#2601) found the showcase
had ZERO list views using @objectstack/spec ListViewSchema.sort's bare
STRING form ('field [asc|desc]') — only the {field,order}[] array form —
which is exactly why the 'schema.sort.map is not a function' crash lurked
undetected. Add sort: 'estimate_hours desc' to the Task List (tabular) view
as a live coverage fixture so the string form is exercised by any browser
dogfood / coverage pass.

Browser-verified end-to-end on latest main (objectui + framework): the list
renders 10 records with no crash, no error boundary, no sort-map error, and
the Estimate column is correctly descending (60→40→30→24→20→18→16→16→12→8).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01HG5LQnPbQbjAAyofghzz3Z

Author: claude

examples/app-showcase/src/ui/views/task.view.ts

@@ -98,6 +98,13 @@ export const TaskViews = defineView({
         { field: 'estimate_hours' },
       ],
 
+      // @objectstack/spec ListViewSchema.sort accepts a bare STRING
+      // ("field [asc|desc]"), not only the {field,order}[] array form. This
+      // is the exact shape that used to crash the renderer with
+      // "schema.sort.map is not a function" (objectui#2601) — kept here as a
+      // live coverage fixture so a real list view exercises the string form.
+      sort: 'estimate_hours desc',
+
       // ADR-0053 — NO `userFilters` here: on an object list view ("views"
       // mode) the console suppresses them by design (the view switcher is
       // the only nav control; objectui warns since #2220). End-user filter