feat: add bulk operations to vendor pages

Add selection and bulk actions to products, orders, and inventory:
- Products: bulk activate/deactivate, feature/unfeature, delete
- Orders: bulk status update, CSV export
- Inventory: bulk stock adjustment, CSV export

All pages include select-all checkbox, row selection highlighting,
and action bars with operation buttons.

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

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

static/vendor/js/inventory.js

@@ -65,6 +65,14 @@ function vendorInventory() {
             quantity: 0
         },
 
+        // Bulk operations
+        selectedItems: [],
+        showBulkAdjustModal: false,
+        bulkAdjustForm: {
+            quantity: 0,
+            reason: ''
+        },
+
         // Debounce timer
         searchTimeout: null,
 
@@ -109,6 +117,16 @@ function vendorInventory() {
             return pages;
         },
 
+        // Computed: Check if all visible items are selected
+        get allSelected() {
+            return this.inventory.length > 0 && this.selectedItems.length === this.inventory.length;
+        },
+
+        // Computed: Check if some but not all items are selected
+        get someSelected() {
+            return this.selectedItems.length > 0 && this.selectedItems.length < this.inventory.length;
+        },
+
         async init() {
             vendorInventoryLog.info('Inventory init() called');
 
@@ -360,6 +378,130 @@ function vendorInventory() {
                 this.pagination.page = pageNum;
                 this.loadInventory();
             }
+        },
+
+        // ============================================================================
+        // BULK OPERATIONS
+        // ============================================================================
+
+        /**
+         * Toggle select all items on current page
+         */
+        toggleSelectAll() {
+            if (this.allSelected) {
+                this.selectedItems = [];
+            } else {
+                this.selectedItems = this.inventory.map(i => i.id);
+            }
+        },
+
+        /**
+         * Toggle selection of a single item
+         */
+        toggleSelect(itemId) {
+            const index = this.selectedItems.indexOf(itemId);
+            if (index === -1) {
+                this.selectedItems.push(itemId);
+            } else {
+                this.selectedItems.splice(index, 1);
+            }
+        },
+
+        /**
+         * Check if item is selected
+         */
+        isSelected(itemId) {
+            return this.selectedItems.includes(itemId);
+        },
+
+        /**
+         * Clear all selections
+         */
+        clearSelection() {
+            this.selectedItems = [];
+        },
+
+        /**
+         * Open bulk adjust modal
+         */
+        openBulkAdjustModal() {
+            if (this.selectedItems.length === 0) return;
+            this.bulkAdjustForm = {
+                quantity: 0,
+                reason: ''
+            };
+            this.showBulkAdjustModal = true;
+        },
+
+        /**
+         * Execute bulk stock adjustment
+         */
+        async bulkAdjust() {
+            if (this.selectedItems.length === 0 || this.bulkAdjustForm.quantity === 0) return;
+
+            this.saving = true;
+            try {
+                let successCount = 0;
+                for (const itemId of this.selectedItems) {
+                    const item = this.inventory.find(i => i.id === itemId);
+                    if (item) {
+                        try {
+                            await apiClient.post(`/vendor/${this.vendorCode}/inventory/adjust`, {
+                                product_id: item.product_id,
+                                location: item.location,
+                                quantity: this.bulkAdjustForm.quantity,
+                                reason: this.bulkAdjustForm.reason || 'Bulk adjustment'
+                            });
+                            successCount++;
+                        } catch (error) {
+                            vendorInventoryLog.warn(`Failed to adjust item ${itemId}:`, error);
+                        }
+                    }
+                }
+                Utils.showToast(`${successCount} item(s) adjusted by ${this.bulkAdjustForm.quantity > 0 ? '+' : ''}${this.bulkAdjustForm.quantity}`, 'success');
+                this.showBulkAdjustModal = false;
+                this.clearSelection();
+                await this.loadInventory();
+            } catch (error) {
+                vendorInventoryLog.error('Bulk adjust failed:', error);
+                Utils.showToast(error.message || 'Failed to adjust inventory', 'error');
+            } finally {
+                this.saving = false;
+            }
+        },
+
+        /**
+         * Export selected items as CSV
+         */
+        exportSelectedItems() {
+            if (this.selectedItems.length === 0) return;
+
+            const selectedData = this.inventory.filter(i => this.selectedItems.includes(i.id));
+
+            // Build CSV content
+            const headers = ['Product', 'SKU', 'Location', 'Quantity', 'Low Stock Threshold', 'Status'];
+            const rows = selectedData.map(i => [
+                i.product_name || '-',
+                i.sku || '-',
+                i.location || 'Default',
+                i.quantity || 0,
+                i.low_stock_threshold || 5,
+                this.getStockStatus(i)
+            ]);
+
+            const csvContent = [
+                headers.join(','),
+                ...rows.map(row => row.map(cell => `"${cell}"`).join(','))
+            ].join('\n');
+
+            // Download
+            const blob = new Blob([csvContent], { type: 'text/csv;charset=utf-8;' });
+            const link = document.createElement('a');
+            link.href = URL.createObjectURL(blob);
+            link.download = `inventory_export_${new Date().toISOString().split('T')[0]}.csv`;
+            link.click();
+
+            Utils.showToast(`Exported ${selectedData.length} item(s)`, 'success');
         }
     };
 }