Fix two critical bugs in v1.1.9

Bug 1: Admin - Both General and Composable tabs visible on initial load
- Added explicit display:none to #composable_product_data panel
- Panel now hidden by default, shows only when product-type-composable class is present
- Prevents both tabs showing simultaneously on new product creation

Bug 2: Frontend - No feedback when no products configured
- Added empty state message when products array is empty
- Users now see helpful message instead of blank grid
- Cleared Twig cache to ensure template changes take effect

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

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

assets/css/admin.css

@@ -4,10 +4,17 @@
  * @package WC_Composable_Product
  */
 
+/* Hide composable panel by default */
 #composable_product_data {
+    display: none;
     padding: 12px;
 }
 
+/* Show composable panel when composable type is selected */
+body.product-type-composable #composable_product_data {
+    display: block;
+}
+
 .composable_criteria_group {
     border-top: 1px solid #eee;
     padding-top: 12px;