Implement comprehensive improvement plan (Phases 1-6)

Security (Phase 1-2):
- Add SecurityHeadersMiddleware with CSP, X-Frame-Options, etc.
- Add RateLimitMiddleware for API rate limiting
- Add security event logging to AuditLogModel
- Add ResponseHelper for standardized API responses
- Update config.php with security constants

Database (Phase 3):
- Add migration 014 for additional indexes
- Add migration 015 for ticket dependencies
- Add migration 016 for ticket attachments
- Add migration 017 for recurring tickets
- Add migration 018 for custom fields

Features (Phase 4-5):
- Add ticket dependencies with DependencyModel and API
- Add duplicate detection with check_duplicates API
- Add file attachments with AttachmentModel and upload/download APIs
- Add @mentions with autocomplete and highlighting
- Add quick actions on dashboard rows

Collaboration (Phase 5):
- Add mention extraction in CommentModel
- Add mention autocomplete dropdown in ticket.js
- Add mention highlighting CSS styles

Admin & Export (Phase 6):
- Add StatsModel for dashboard widgets
- Add dashboard stats cards (open, critical, unassigned, etc.)
- Add CSV/JSON export via export_tickets API
- Add rich text editor toolbar in markdown.js
- Add RecurringTicketModel with cron job
- Add CustomFieldModel for per-category fields
- Add admin views: RecurringTickets, CustomFields, Workflow,
  Templates, AuditLog, UserActivity
- Add admin APIs: manage_workflows, manage_templates,
  manage_recurring, custom_fields, get_users
- Add admin routes in index.php

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

controllers/DashboardController.php

@@ -1,16 +1,19 @@
 <?php
 require_once 'models/TicketModel.php';
 require_once 'models/UserPreferencesModel.php';
+require_once 'models/StatsModel.php';
 
 class DashboardController {
     private $ticketModel;
     private $prefsModel;
+    private $statsModel;
     private $conn;
 
     public function __construct($conn) {
         $this->conn = $conn;
         $this->ticketModel = new TicketModel($conn);
         $this->prefsModel = new UserPreferencesModel($conn);
+        $this->statsModel = new StatsModel($conn);
     }
     
     public function index() {
@@ -71,28 +74,37 @@ class DashboardController {
         $tickets = $result['tickets'];
         $totalTickets = $result['total'];
         $totalPages = $result['pages'];
-        
+
+        // Load dashboard statistics
+        $stats = $this->statsModel->getAllStats();
+
         // Load the dashboard view
         include 'views/DashboardView.php';
     }
 
     private function getCategories() {
         $sql = "SELECT DISTINCT category FROM tickets WHERE category IS NOT NULL ORDER BY category";
-        $result = $this->conn->query($sql);
+        $stmt = $this->conn->prepare($sql);
+        $stmt->execute();
+        $result = $stmt->get_result();
         $categories = [];
-        while($row = $result->fetch_assoc()) {
+        while ($row = $result->fetch_assoc()) {
             $categories[] = $row['category'];
         }
+        $stmt->close();
         return $categories;
     }
-    
+
     private function getTypes() {
         $sql = "SELECT DISTINCT type FROM tickets WHERE type IS NOT NULL ORDER BY type";
-        $result = $this->conn->query($sql);
+        $stmt = $this->conn->prepare($sql);
+        $stmt->execute();
+        $result = $stmt->get_result();
         $types = [];
-        while($row = $result->fetch_assoc()) {
+        while ($row = $result->fetch_assoc()) {
             $types[] = $row['type'];
         }
+        $stmt->close();
         return $types;
     }
 }