fix: add missing ban icon and fix products tab loading

- Add 'ban' icon to icons.js for empty state displays
- Fix products tab to load when no vendor filter is selected

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

static/admin/js/marketplace-letzshop.js

@@ -160,7 +160,8 @@ function adminMarketplaceLetzshop() {
                 marketplaceLetzshopLog.info('Tab changed to:', newTab);
                 if (newTab === 'jobs' && this.selectedVendor) {
                     await this.loadJobs();
-                } else if (newTab === 'products' && this.selectedVendor) {
+                } else if (newTab === 'products') {
+                    // Load products for selected vendor or all Letzshop products
                     await this.loadProducts();
                 } else if (newTab === 'orders') {
                     await this.loadOrders();