Fix type safety and TDS class naming issues

- bulk_operation.php: replace is_numeric() with strict int cast+equality to reject scientific notation
- AttachmentModel.php: fix bind_param type strings (s→i for integer ticket IDs)
- CommentModel.php: use strict !== comparison with (int) cast for user_id ownership checks
- ticket.js: replace all non-TDS class names (text-amber→lt-text-amber, btn→lt-btn variants, etc.)

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

models/CommentModel.php

@@ -240,7 +240,7 @@ class CommentModel {
             return ['success' => false, 'error' => 'Comment not found'];
         }
 
-        if ($comment['user_id'] != $userId && !$isAdmin) {
+        if ($comment['user_id'] !== (int)$userId && !$isAdmin) {
             return ['success' => false, 'error' => 'You do not have permission to edit this comment'];
         }
 
@@ -286,7 +286,7 @@ class CommentModel {
             return ['success' => false, 'error' => 'Comment not found'];
         }
 
-        if ($comment['user_id'] != $userId && !$isAdmin) {
+        if ($comment['user_id'] !== (int)$userId && !$isAdmin) {
             return ['success' => false, 'error' => 'You do not have permission to delete this comment'];
         }