fix: enforce top-down state cascade and prevent base product hiding

shop/components/order-wizard.tsx

@@ -390,6 +390,20 @@ export function OrderWizard({
         [catId]: { productId: nextProductId, productIds: nextProductIds, moduleIds: [] },
       }
 
+      // Kaskaden-Bereinigung: Entferne inkompatible Module in anderen Kategorien
+      const newProduct = products.find(p => p.id === nextProductId)
+      categories.forEach(c => {
+        if (c.id === catId) return
+        const s = next[c.id]
+        if (s && s.moduleIds.length > 0) {
+          s.moduleIds = s.moduleIds.filter(mId => {
+            // Prüfe ob das neue Basis-Produkt dieses Modul ausschließt
+            const isExcluded = newProduct?.exclusions?.includes(mId)
+            return !isExcluded
+          })
+        }
+      })
+
       if (shouldReset) {
         // Reset all other categories
         categories.forEach(c => {
@@ -429,7 +443,7 @@ export function OrderWizard({
             next[c.id] = {
               productId: validProductIds[0] || null,
               productIds: validProductIds,
-              moduleIds: []
+              moduleIds: s.moduleIds
             }
           } else if (s?.productId) {
             const prod = products.find(p => p.id === s.productId)
@@ -902,27 +916,14 @@ export function OrderWizard({
                         .map(([, s]) => s.productId)
                         .filter((id): id is string => !!id)
 
-                      // Filter products based on display flags and mutual exclusions
+                      // Filter products based on display flags (do not hide due to exclusions to prevent UI deadlocks)
                       const catProducts = products.filter(p => {
                         if (p.category_id !== cat.id) return false
 
                         const matchesInterval = selectedBillingInterval === 'one_time'
                           ? p.show_in_kauf !== false
                           : p.show_in_abo !== false
-                        if (!matchesInterval) return false
+                        return matchesInterval
-
-                        // Check if p is excluded by any other selected product
-                        const isExcludedByOthers = otherSelectedProductIds.some(otherId => {
-                          const otherProd = products.find(prod => prod.id === otherId)
-                          return otherProd?.exclusions?.includes(p.id)
-                        })
-                        if (isExcludedByOthers) return false
-
-                        // Check if p excludes any other selected product
-                        const excludesOthers = p.exclusions?.some(exId => otherSelectedProductIds.includes(exId))
-                        if (excludesOthers) return false
-
-                        return true
                       })
                       const sel = selections[cat.id]
                       const selectedProduct = catProducts.find(p => p.id === sel?.productId) ?? null