Fix scan output file paths and improve notification system

- Save JSON/HTML/ZIP paths to database when scans complete
- Remove orphaned scan-config-id reference causing JS errors
- Add showAlert function to scan_detail.html and scans.html
- Increase notification z-index to 9999 for modal visibility
- Replace inline alert creation with consistent toast notifications

app/web/templates/base.html

@@ -108,7 +108,7 @@
     </div>
 
     <!-- Global notification container - always above modals -->
-    <div id="notification-container" style="position: fixed; top: 20px; right: 20px; z-index: 1100; min-width: 300px;"></div>
+    <div id="notification-container" style="position: fixed; top: 20px; right: 20px; z-index: 9999; min-width: 300px;"></div>
 
     <script src="https://cdn.jsdelivr.net/npm/bootstrap@5.3.0/dist/js/bootstrap.bundle.min.js"></script>
     {% block scripts %}{% endblock %}