fix: add missing CSS classes + clean up remaining inline styles

- Add .lt-modal-sm (max 360px) and .lt-modal-header--danger variant used
  in JS-generated bulk delete confirmation modal (no CSS = unstyled header)
- Add .lt-badge-sm for compact inline badges (comment counts, group tags)
- Add .lt-kv-row { display:contents } with .lt-kv-label/.lt-kv-value rules
  (was missing from previous commit — added in base.css)
- Replace style="text-align:center" with .lt-text-center in JS modal body
- Replace style="flex-direction:column" with .lt-flex-col on .lt-btn-group

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

assets/js/dashboard.js

@@ -840,7 +840,7 @@ function showBulkDeleteModal() {
                     <span class="lt-modal-title" id="bulkDeleteModalTitle">[ ! ] DELETE ${ticketIds.length} TICKET(S)</span>
                     <button class="lt-modal-close" data-modal-close aria-label="Close">✕</button>
                 </div>
-                <div class="lt-modal-body" style="text-align:center">
+                <div class="lt-modal-body lt-text-center">
                     <p class="lt-text-danger lt-text-sm">This action cannot be undone!</p>
                     <p class="lt-text-cyan">You are about to permanently delete ${ticketIds.length} ticket(s).<br>All associated comments and history will be lost.</p>
                 </div>