Implement Excel webhook integration

Features:
- Migration 0007: shipping_date column with automatic next-business-day calculation
- New function trigger_excel_webhook() in order-import.php
- SQL query for extracting Excel data from ERP database
- Integration after successful order import
- Documentation for n8n Postgres node configuration

Changes:
1. db/migrations/0007_phase1_excel_webhook.sql - adds shipping_date column, trigger, next-business-day function
2. order-import.php - adds trigger_excel_webhook() function and integration point
3. docs/EXAKTE_POSTGRES_QUERY.sql - exact SQL query for n8n Postgres node
4. docs/N8N_POSTGRES_QUERY.md - comprehensive documentation
5. docs/N8N_POSTGRES_NODE.* - n8n node configurations
6. docs/N8N_EXCEL_WORKFLOW.json - complete workflow JSON
7. docs/N8N_NODE_COPY_PASTE.md - copy-paste ready instructions

The implementation triggers an Excel webhook after every successful order import, sending all necessary data for Excel bookkeeping to n8n.

order-import.php

@@ -348,6 +348,83 @@ function trigger_shipping_label_flow(array $order, array $localEnv): array
     ];
 }
 
+function trigger_excel_webhook(PDO $pdo, int $orderId, array $localEnv): array
+{
+    $url = env_value('N8N_OUTBOUND_URL_ADRESSE', $localEnv);
+    if ($url === '' || strpos($url, 'excel_befuellen') === false) {
+        return [
+            'enabled' => false,
+            'ok' => false,
+            'message' => 'Excel webhook URL not configured or incorrect (must contain "excel_befuellen")',
+        ];
+    }
+    
+    // SQL Query for all Excel data (without comments for n8n compatibility)
+    $sql = "
+        SELECT 
+            so.external_ref AS \"Bestellnummer\",
+            TO_CHAR(so.order_date, 'YYYY-MM-DD\"T\"HH24:MI:SS') AS \"Bestelldatum\",
+            TO_CHAR(so.shipping_date, 'YYYY-MM-DD') AS \"Versanddatum\",
+            COALESCE(ad.first_name, '') AS \"Vorname\",
+            COALESCE(ad.last_name, '') AS \"Nachname\",
+            COALESCE(ad.street, '') AS \"Strasse\",
+            COALESCE(ad.house_number, '') AS \"Hausnummer\",
+            COALESCE(ad.zip, '') AS \"PLZ\",
+            COALESCE(ad.city, '') AS \"Stadt\",
+            COALESCE(ad.country_name, '') AS \"Land\",
+            COALESCE(pm.code, '') AS \"Zahlungsart\",
+            COALESCE(so.amount_net, 0) AS \"Gesamtbetrag_netto\",
+            COALESCE(so.amount_shipping, 0) AS \"Versandkosten\",
+            COALESCE(so.total_amount, 0) AS \"Gesamtbetrag_brutto\",
+            COALESCE(so.amount_discount, 0) AS \"Rabatt\",
+            COALESCE(SUM(CASE WHEN p.id = 8 THEN a.qty ELSE 0 END), 0) AS \"#_ChagaFlaschen\",
+            COALESCE(SUM(CASE WHEN p.id = 5 THEN a.qty ELSE 0 END), 0) AS \"#_ReishiFlaschen\",
+            COALESCE(SUM(CASE WHEN p.id = 9 THEN a.qty ELSE 0 END), 0) AS \"#_ShiitakeFlaschen\",
+            COALESCE(SUM(CASE WHEN p.id = 6 THEN a.qty ELSE 0 END), 0) AS \"#_LionsManeFlaschen\"
+        FROM sales_order so
+        LEFT JOIN address ad ON so.party_id = ad.party_id AND ad.type = 'shipping'
+        LEFT JOIN payment_method pm ON so.payment_method_id = pm.id
+        LEFT JOIN sales_order_line sol ON so.id = sol.sales_order_id
+        LEFT JOIN sales_order_line_lot_allocation a ON sol.id = a.sales_order_line_id
+        LEFT JOIN product p ON a.product_id = p.id AND p.status = 'active'
+        WHERE so.id = :order_id
+        GROUP BY so.id, ad.id, pm.id
+    ";
+    
+    $stmt = $pdo->prepare($sql);
+    $stmt->execute([':order_id' => $orderId]);
+    $data = $stmt->fetch();
+    
+    if (!$data) {
+        return [
+            'enabled' => true,
+            'ok' => false,
+            'message' => 'Order data not found or no product allocations',
+        ];
+    }
+    
+    // Authentication headers (same mechanism as shipping_label_flow)
+    $headers = [];
+    $secret = env_value('N8N_WEBHOOK_SECRET', $localEnv);
+    if ($secret !== '') {
+        $headers['X-Webhook-Secret'] = $secret;
+        $headers['X-N8N-Secret'] = $secret;
+        $headers['X-API-Key'] = $secret;
+        $headers['Authorization'] = 'Bearer ' . $secret;
+    }
+    
+    $result = post_json($url, $data, $headers, 20);
+    
+    return [
+        'enabled' => true,
+        'ok' => $result['ok'],
+        'status' => $result['status'],
+        'url' => $url,
+        'message' => $result['ok'] ? 'Excel webhook triggered' : ($result['error'] !== '' ? $result['error'] : 'Excel webhook returned non-2xx'),
+        'responseBody' => $result['body'],
+    ];
+}
+
 function find_or_create_party(PDO $pdo, array $data): int
 {
     $email = trim((string) ($data['EmailKunde'] ?? ''));
@@ -1520,6 +1597,7 @@ try {
     $pdo->commit();
 
     $labelTrigger = trigger_shipping_label_flow($data, $env);
+    $excelTrigger = trigger_excel_webhook($pdo, $orderId, $env);
 
     json_response(200, [
         'ok' => true,
@@ -1529,6 +1607,7 @@ try {
         'inventory' => $inventory,
         'inventoryRollback' => $inventoryRollback,
         'labelTrigger' => $labelTrigger,
+        'excelTrigger' => $excelTrigger,
     ]);
 } catch (Throwable $e) {
     if (isset($pdo) && $pdo instanceof PDO && $pdo->inTransaction()) {