feat: add detailed logging to add to cart functionality for debugging

Added comprehensive console logging to track:
- Cart eligibility checks
- API request URL and payload
- Response status and data
- Error details

This will help identify why items aren't being added to cart.

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

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

app/templates/shop/product.html

@@ -354,28 +354,50 @@ document.addEventListener('alpine:init', () => {
 
         // Add to cart
         async addToCart() {
-            if (!this.canAddToCart) return;
+            if (!this.canAddToCart) {
+                console.warn('[SHOP] Cannot add to cart:', {
+                    canAddToCart: this.canAddToCart,
+                    isActive: this.product?.is_active,
+                    inventory: this.product?.available_inventory,
+                    quantity: this.quantity
+                });
+                return;
+            }
 
             this.addingToCart = true;
 
             try {
-                console.log('[SHOP] Adding to cart:', { productId: this.productId, quantity: this.quantity });
+                const url = `/api/v1/shop/cart/${this.sessionId}/items`;
+                const payload = {
+                    product_id: parseInt(this.productId),
+                    quantity: this.quantity
+                };
 
-                const response = await fetch(
-                    `/api/v1/shop/cart/${this.sessionId}/items`,
-                    {
-                        method: 'POST',
-                        headers: {
-                            'Content-Type': 'application/json'
-                        },
-                        body: JSON.stringify({
-                            product_id: parseInt(this.productId),
-                            quantity: this.quantity
-                        })
-                    }
-                );
+                console.log('[SHOP] Adding to cart:', {
+                    url,
+                    sessionId: this.sessionId,
+                    productId: this.productId,
+                    quantity: this.quantity,
+                    payload
+                });
+
+                const response = await fetch(url, {
+                    method: 'POST',
+                    headers: {
+                        'Content-Type': 'application/json'
+                    },
+                    body: JSON.stringify(payload)
+                });
+
+                console.log('[SHOP] Add to cart response:', {
+                    status: response.status,
+                    ok: response.ok
+                });
 
                 if (response.ok) {
+                    const result = await response.json();
+                    console.log('[SHOP] Add to cart success:', result);
+
                     this.cartCount += this.quantity;
                     this.showToast(
                         `${this.quantity} item(s) added to cart!`,
@@ -386,10 +408,11 @@ document.addEventListener('alpine:init', () => {
                     this.quantity = this.product?.min_quantity || 1;
                 } else {
                     const error = await response.json();
+                    console.error('[SHOP] Add to cart error response:', error);
                     throw new Error(error.detail || 'Failed to add to cart');
                 }
             } catch (error) {
-                console.error('[SHOP] Add to cart error:', error);
+                console.error('[SHOP] Add to cart exception:', error);
                 this.showToast(error.message || 'Failed to add to cart', 'error');
             } finally {
                 this.addingToCart = false;