feat(accounting): Skontobedingungen auf Belegen und automatische Skonto-Vorschläge

Ausgangs- und Eingangsbelege erhalten Skontosatz und Frist, mit Vorgaben
bei Kunden und Lieferanten. Das PDF ergänzt automatisch einen Skontohinweis
(oder nutzt neue Textvorlagen-Variablen); bei Schlussrechnungen gilt der
Skonto für die Restforderung. Skontobedingungen werden aus E-Rechnungen
(#SKONTO# und ZUGFeRD) sowie von der KI-Vorbereitung übernommen. Die
Bankzuordnung erkennt Zahlungen abzüglich Skonto innerhalb der Frist und
bietet sie in der Vorschlagsübersicht direkt an. BWA-Erlöse und -Aufwand
berücksichtigen gebuchten Skonto im Zeitraum der Zahlung.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

frontend/pages/createDocument/edit/[[id]].vue

@@ -6,6 +6,7 @@ import {useFunctions} from "~/composables/useFunctions.js";
 import EntityModalButtons from "~/components/EntityModalButtons.vue";
 import { documentTemplateHandlebars } from "~/utils/handlebars";
 import { getTitleSectionMove, moveTitleSection } from "~/utils/documentTitleSections.js";
+import { appendCashDiscountText, buildCashDiscountTerms, formatCashDiscountText, getCashDiscountTemplateContext } from "~/utils/cashDiscount";
 
 const dataStore = useDataStore()
 const profileStore = useProfileStore()
@@ -57,6 +58,8 @@ const itemInfo = ref({
   deliveryDateType: "Lieferdatum",
   dateOfPerformance: null,
   paymentDays: auth.activeTenantData.standardPaymentDays,
+  cashDiscountPercent: null,
+  cashDiscountDays: null,
   payment_type: "transfer",
   outgoingsepamandate: null,
   availableInPortal: false,
@@ -635,7 +638,11 @@ const setupPage = async () => {
         if (optionsToImport.deliveryDate) itemInfo.value.deliveryDate = linkedDocument.deliveryDate
         if (optionsToImport.deliveryDateEnd) itemInfo.value.deliveryDateEnd = linkedDocument.deliveryDateEnd
         if (optionsToImport.documentDate) itemInfo.value.documentDate = linkedDocument.documentDate
-        if (optionsToImport.paymentDays) itemInfo.value.paymentDays = linkedDocument.paymentDays
+        if (optionsToImport.paymentDays) {
+          itemInfo.value.paymentDays = linkedDocument.paymentDays
+          itemInfo.value.cashDiscountPercent = linkedDocument.cashDiscountPercent ?? null
+          itemInfo.value.cashDiscountDays = linkedDocument.cashDiscountDays ?? null
+        }
         if (optionsToImport.payment_type) itemInfo.value.payment_type = linkedDocument.payment_type
         if (optionsToImport.customSurchargePercentage) itemInfo.value.customSurchargePercentage = linkedDocument.customSurchargePercentage
         if (optionsToImport.contactPerson) itemInfo.value.contactPerson = linkedDocument.contactPerson
@@ -663,6 +670,8 @@ const setupPage = async () => {
         itemInfo.value.deliveryDateEnd = linkedDocument.deliveryDateEnd
         itemInfo.value.documentDate = linkedDocument.documentDate
         itemInfo.value.paymentDays = linkedDocument.paymentDays
+        itemInfo.value.cashDiscountPercent = linkedDocument.cashDiscountPercent ?? null
+        itemInfo.value.cashDiscountDays = linkedDocument.cashDiscountDays ?? null
         itemInfo.value.payment_type = linkedDocument.payment_type
         itemInfo.value.customSurchargePercentage = linkedDocument.customSurchargePercentage
         itemInfo.value.contactPerson = linkedDocument.contactPerson
@@ -833,6 +842,10 @@ const setCustomerData = async (customerId, loadOnlyAdress = false) => {
     itemInfo.value.address.country = customer.infoData.country
 
     if (!loadOnlyAdress && customer.customPaymentDays) itemInfo.value.paymentDays = customer.customPaymentDays
+    if (!loadOnlyAdress && customer.customCashDiscountPercent) {
+      itemInfo.value.cashDiscountPercent = customer.customCashDiscountPercent
+      itemInfo.value.cashDiscountDays = customer.customCashDiscountDays ?? null
+    }
     if (!loadOnlyAdress && customer.custom_payment_type) itemInfo.value.payment_type = customer.custom_payment_type
     if (!loadOnlyAdress) {
       itemInfo.value.taxType = normalizeTaxTypeValue(customer.customTaxType)
@@ -1357,6 +1370,17 @@ const documentTotal = computed(() => {
   }
 })
 
+// Skonto bezieht sich bei Schlussrechnungen auf die Restforderung nach Abzug der Abschläge.
+const cashDiscountTerms = computed(() => {
+  if (!["invoices", "advanceInvoices", "serialInvoices"].includes(itemInfo.value.type)) return null
+  return buildCashDiscountTerms({
+    percent: itemInfo.value.cashDiscountPercent,
+    days: itemInfo.value.cashDiscountDays,
+    documentDate: itemInfo.value.documentDate ? dayjs(itemInfo.value.documentDate).format("YYYY-MM-DD") : null,
+    amount: itemInfo.value.type === "invoices" ? documentTotal.value.totalSumToPay : documentTotal.value.totalGross
+  })
+})
+
 const documentReport = computed(() => {
 
   let totalProductsPurchasePrice = 0
@@ -1574,7 +1598,8 @@ const getDocumentData = async () => {
       kundenname: customerData && customerData.name,
       zahlungsziel_in_tagen: itemInfo.paymentDays,
       zahlungsart: itemInfo.payment_type === "transfer" ? "Überweisung" : "Lastschrift",
-      diesel_gesamtverbrauch: (itemInfo.agriculture && itemInfo.agriculture.dieselUsageTotal) && itemInfo.agriculture.dieselUsageTotal
+      diesel_gesamtverbrauch: (itemInfo.agriculture && itemInfo.agriculture.dieselUsageTotal) && itemInfo.agriculture.dieselUsageTotal,
+      ...getCashDiscountTemplateContext(cashDiscountTerms.value)
     }
   }
 
@@ -1684,7 +1709,7 @@ const getDocumentData = async () => {
     ],
     title: itemInfo.value.title,
     description: itemInfo.value.description,
-    endText: templateEndText(generateContext(itemInfo.value, contactData)),
+    endText: appendCashDiscountText(templateEndText(generateContext(itemInfo.value, contactData)), itemInfo.value.endText, cashDiscountTerms.value),
     startText: templateStartText(generateContext(itemInfo.value, contactData)),
     rows: rows,
     totalArray: [
@@ -1819,6 +1844,8 @@ const saveSerialInvoice = async () => {
     project: normalizeEntityId(itemInfo.value.project),
     costcentre: itemInfo.value.costcentre,
     paymentDays: itemInfo.value.paymentDays,
+    cashDiscountPercent: itemInfo.value.cashDiscountPercent === "" || itemInfo.value.cashDiscountPercent === null ? null : Number(itemInfo.value.cashDiscountPercent),
+    cashDiscountDays: itemInfo.value.cashDiscountDays === "" || itemInfo.value.cashDiscountDays === null ? null : Number(itemInfo.value.cashDiscountDays),
     payment_type: itemInfo.value.payment_type,
     outgoingsepamandate: normalizeEntityId(itemInfo.value.outgoingsepamandate),
     deliveryDateType: "Leistungszeitraum",
@@ -1935,6 +1962,8 @@ const saveDocument = async (state, resetup = false) => {
     deliveryDate: itemInfo.value.deliveryDate,
     deliveryDateEnd: itemInfo.value.deliveryDateEnd,
     paymentDays: itemInfo.value.paymentDays,
+    cashDiscountPercent: itemInfo.value.cashDiscountPercent === "" || itemInfo.value.cashDiscountPercent === null ? null : Number(itemInfo.value.cashDiscountPercent),
+    cashDiscountDays: itemInfo.value.cashDiscountDays === "" || itemInfo.value.cashDiscountDays === null ? null : Number(itemInfo.value.cashDiscountDays),
     payment_type: itemInfo.value.payment_type,
     outgoingsepamandate: normalizeEntityId(itemInfo.value.outgoingsepamandate),
     deliveryDateType: itemInfo.value.deliveryDateType,
@@ -2690,6 +2719,39 @@ const setRowData = async (row, service = {sellingPriceComposed: {}}, product = {
                       class="w-full"
                   />
                 </UFormField>
+                <UFormField
+                    v-if="['invoices', 'advanceInvoices', 'serialInvoices'].includes(itemInfo.type)"
+                    class="min-w-0 flex-1"
+                    label="Skonto:"
+                    :help="cashDiscountTerms ? formatCashDiscountText(cashDiscountTerms) : undefined"
+                >
+                  <div class="flex gap-1">
+                    <UInput
+                        type="number"
+                        step="0.01"
+                        min="0"
+                        max="10"
+                        placeholder="%"
+                        v-model="itemInfo.cashDiscountPercent"
+                        class="w-full"
+                    >
+                      <template #trailing>
+                        <span class="text-gray-500 dark:text-gray-400 text-xs">%</span>
+                      </template>
+                    </UInput>
+                    <UInput
+                        type="number"
+                        min="0"
+                        placeholder="Tage"
+                        v-model="itemInfo.cashDiscountDays"
+                        class="w-full"
+                    >
+                      <template #trailing>
+                        <span class="text-gray-500 dark:text-gray-400 text-xs">Tage</span>
+                      </template>
+                    </UInput>
+                  </div>
+                </UFormField>
                 <UFormField
                     class="min-w-0 flex-1"
                     label="Individueller Aufschlag:"