feat: add Create Product and CRUD actions to vendor-products page

- Add "Create Product" button in header
- Update actions column to View, Edit, Delete
- Add create/edit pages with forms and vendor selector
- Add POST/PATCH API endpoints for vendor products
- Add create_product and update_product service methods

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

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

static/admin/js/vendor-product-create.js

@@ -0,0 +1,164 @@
+// static/admin/js/vendor-product-create.js
+/**
+ * Admin vendor product create page logic
+ * Create new vendor product entries
+ */
+
+const adminVendorProductCreateLog = window.LogConfig.loggers.adminVendorProductCreate ||
+    window.LogConfig.createLogger('adminVendorProductCreate', false);
+
+adminVendorProductCreateLog.info('Loading...');
+
+function adminVendorProductCreate() {
+    adminVendorProductCreateLog.info('adminVendorProductCreate() called');
+
+    return {
+        // Inherit base layout state
+        ...data(),
+
+        // Set page identifier
+        currentPage: 'vendor-products',
+
+        // Loading states
+        saving: false,
+
+        // Tom Select instance
+        vendorSelectInstance: null,
+
+        // Form data
+        form: {
+            vendor_id: null,
+            title: '',
+            brand: '',
+            vendor_sku: '',
+            gtin: '',
+            price: null,
+            currency: 'EUR',
+            availability: '',
+            is_active: true,
+            is_featured: false,
+            is_digital: false,
+            description: ''
+        },
+
+        async init() {
+            adminVendorProductCreateLog.info('Vendor Product Create init() called');
+
+            // Guard against multiple initialization
+            if (window._adminVendorProductCreateInitialized) {
+                adminVendorProductCreateLog.warn('Already initialized, skipping');
+                return;
+            }
+            window._adminVendorProductCreateInitialized = true;
+
+            // Initialize Tom Select
+            this.initVendorSelect();
+
+            adminVendorProductCreateLog.info('Vendor Product Create initialization complete');
+        },
+
+        /**
+         * Initialize Tom Select for vendor autocomplete
+         */
+        initVendorSelect() {
+            const selectEl = this.$refs.vendorSelect;
+            if (!selectEl) {
+                adminVendorProductCreateLog.warn('Vendor select element not found');
+                return;
+            }
+
+            // Wait for Tom Select to be available
+            if (typeof TomSelect === 'undefined') {
+                adminVendorProductCreateLog.warn('TomSelect not loaded, retrying in 100ms');
+                setTimeout(() => this.initVendorSelect(), 100);
+                return;
+            }
+
+            this.vendorSelectInstance = new TomSelect(selectEl, {
+                valueField: 'id',
+                labelField: 'name',
+                searchField: ['name', 'vendor_code'],
+                placeholder: 'Search vendor...',
+                load: async (query, callback) => {
+                    try {
+                        const response = await apiClient.get('/admin/vendors', {
+                            search: query,
+                            limit: 50
+                        });
+                        callback(response.vendors || []);
+                    } catch (error) {
+                        adminVendorProductCreateLog.error('Failed to search vendors:', error);
+                        callback([]);
+                    }
+                },
+                render: {
+                    option: (data, escape) => {
+                        return `<div class="flex items-center justify-between py-1">
+                            <span>${escape(data.name)}</span>
+                            <span class="text-xs text-gray-400 font-mono">${escape(data.vendor_code || '')}</span>
+                        </div>`;
+                    },
+                    item: (data, escape) => {
+                        return `<div>${escape(data.name)}</div>`;
+                    }
+                },
+                onChange: (value) => {
+                    this.form.vendor_id = value ? parseInt(value) : null;
+                }
+            });
+
+            adminVendorProductCreateLog.info('Vendor select initialized');
+        },
+
+        /**
+         * Create the product
+         */
+        async createProduct() {
+            if (!this.form.vendor_id) {
+                Utils.showToast('Please select a vendor', 'error');
+                return;
+            }
+
+            if (!this.form.title) {
+                Utils.showToast('Please enter a product title', 'error');
+                return;
+            }
+
+            this.saving = true;
+
+            try {
+                // Build create payload
+                const payload = {
+                    vendor_id: this.form.vendor_id,
+                    title: this.form.title,
+                    brand: this.form.brand || null,
+                    vendor_sku: this.form.vendor_sku || null,
+                    gtin: this.form.gtin || null,
+                    price: this.form.price ? parseFloat(this.form.price) : null,
+                    currency: this.form.currency || 'EUR',
+                    availability: this.form.availability || null,
+                    is_active: this.form.is_active,
+                    is_featured: this.form.is_featured,
+                    is_digital: this.form.is_digital,
+                    description: this.form.description || null
+                };
+
+                const response = await apiClient.post('/admin/vendor-products', payload);
+
+                adminVendorProductCreateLog.info('Product created:', response.id);
+
+                Utils.showToast('Product created successfully', 'success');
+
+                // Redirect to the new product's detail page
+                setTimeout(() => {
+                    window.location.href = `/admin/vendor-products/${response.id}`;
+                }, 1000);
+            } catch (error) {
+                adminVendorProductCreateLog.error('Failed to create product:', error);
+                Utils.showToast(error.message || 'Failed to create product', 'error');
+            } finally {
+                this.saving = false;
+            }
+        }
+    };
+}