fix: Resolve multiple UI and API bugs

- Remove is_active filter from get_users.php (column doesn't exist)
- Fix ticket ID validation regex in upload_attachment.php (9-digit format)
- Fix createSettingsModal reference to use openSettingsModal from settings.js
- Add error handling for dependencies tab to prevent infinite loading
- Add try-catch wrapper to ticket_dependencies.php API
- Make export dropdown visible only when tickets are selected
- Export only selected tickets instead of all filtered tickets

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

assets/js/dashboard.js

@@ -117,7 +117,10 @@ function initSettingsModal() {
     if (settingsIcon) {
         settingsIcon.addEventListener('click', function(e) {
             e.preventDefault();
-            createSettingsModal();
+            // openSettingsModal is defined in settings.js
+            if (typeof openSettingsModal === 'function') {
+                openSettingsModal();
+            }
         });
     }
 }
@@ -482,6 +485,8 @@ function updateSelectionCount() {
     const count = checkboxes.length;
     const toolbar = document.querySelector('.bulk-actions-inline');
     const countDisplay = document.getElementById('selected-count');
+    const exportDropdown = document.getElementById('exportDropdown');
+    const exportCount = document.getElementById('exportCount');
 
     if (toolbar && countDisplay) {
         if (count > 0) {
@@ -491,6 +496,16 @@ function updateSelectionCount() {
             toolbar.style.display = 'none';
         }
     }
+
+    // Show/hide export dropdown based on selection
+    if (exportDropdown) {
+        if (count > 0) {
+            exportDropdown.style.display = '';
+            if (exportCount) exportCount.textContent = count;
+        } else {
+            exportDropdown.style.display = 'none';
+        }
+    }
 }
 
 function getSelectedTicketIds() {
@@ -1339,3 +1354,47 @@ function performQuickAssign(ticketId) {
         toast.error('Error updating assignment', 4000);
     });
 }
+
+/**
+ * Toggle export dropdown menu
+ */
+function toggleExportMenu(event) {
+    event.stopPropagation();
+    const dropdown = document.getElementById('exportDropdown');
+    const content = document.getElementById('exportDropdownContent');
+    if (dropdown && content) {
+        dropdown.classList.toggle('open');
+    }
+}
+
+// Close export dropdown when clicking outside
+document.addEventListener('click', function(event) {
+    const dropdown = document.getElementById('exportDropdown');
+    if (dropdown && !dropdown.contains(event.target)) {
+        dropdown.classList.remove('open');
+    }
+});
+
+/**
+ * Export selected tickets to CSV or JSON
+ */
+function exportSelectedTickets(format) {
+    const ticketIds = getSelectedTicketIds();
+
+    if (ticketIds.length === 0) {
+        toast.warning('No tickets selected', 2000);
+        return;
+    }
+
+    // Build URL with selected ticket IDs
+    const params = new URLSearchParams();
+    params.set('format', format);
+    params.set('ticket_ids', ticketIds.join(','));
+
+    // Trigger download
+    window.location.href = '/api/export_tickets.php?' + params.toString();
+
+    // Close dropdown
+    const dropdown = document.getElementById('exportDropdown');
+    if (dropdown) dropdown.classList.remove('open');
+}