Migrate status and priority display to lt-status/lt-priority design system classes

DashboardView.php:
- Table status column: replace status-{slug} with lt-status lt-status-{slug} for consistent [● Status] bracket decoration from base.css
- Table priority column: replace raw number with lt-priority lt-p{N} empty span for [▲▲ P1 CRITICAL] style badges

dashboard.js:
- Kanban card priority badge: replace card-priority p{N} with lt-priority lt-p{N} to use the design system badge

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

assets/js/dashboard.js

@@ -1348,7 +1348,7 @@ function populateKanbanCards() {
             card.innerHTML = `
                 <div class="card-header">
                     <span class="card-id">#${lt.escHtml(ticketId)}</span>
-                    <span class="card-priority p${priority}">P${priority}</span>
+                    <span class="lt-priority lt-p${priority}"></span>
                 </div>
                 <div class="card-title">${lt.escHtml(title)}</div>
                 <div class="card-footer">