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.

docs/N8N_POSTGRES_NODE.json

@@ -0,0 +1,26 @@
+{
+  "name": "Excel Daten aus ERP abfragen",
+  "type": "n8n-nodes-base.postgres",
+  "typeVersion": 2.1,
+  "position": [0, 0],
+  "credentials": {
+    "postgres": {
+      "id": "YOUR_CREDENTIAL_ID_HERE",
+      "name": "ERP Naurua Database"
+    }
+  },
+  "parameters": {
+    "operation": "executeQuery",
+    "query": "SELECT \n    -- Bestellinformationen\n    so.external_ref AS \"Bestellnummer\",\n    TO_CHAR(so.order_date, 'YYYY-MM-DD\"T\"HH24:MI:SS') AS \"Bestelldatum\",\n    TO_CHAR(so.shipping_date, 'YYYY-MM-DD') AS \"Versanddatum\",\n    \n    -- Kundenadresse (Lieferadresse)\n    COALESCE(ad.first_name, '') AS \"Vorname\",\n    COALESCE(ad.last_name, '') AS \"Nachname\",\n    COALESCE(ad.street, '') AS \"Strasse\",\n    COALESCE(ad.house_number, '') AS \"Hausnummer\",\n    COALESCE(ad.zip, '') AS \"PLZ\",\n    COALESCE(ad.city, '') AS \"Stadt\",\n    COALESCE(ad.country_name, '') AS \"Land\",\n    \n    -- Zahlungs- und Betragsinformationen\n    COALESCE(pm.code, '') AS \"Zahlungsart\",\n    COALESCE(so.amount_net, 0) AS \"Gesamtbetrag_netto\",\n    COALESCE(so.amount_shipping, 0) AS \"Versandkosten\",\n    COALESCE(so.total_amount, 0) AS \"Gesamtbetrag_brutto\",\n    COALESCE(so.amount_discount, 0) AS \"Rabatt\",\n    \n    -- Produktzählungen (nur aktive Produkte)\n    COALESCE(SUM(CASE WHEN p.id = 8 THEN a.qty ELSE 0 END), 0) AS \"#_ChagaFlaschen\",      -- CHAGA (ID 8)\n    COALESCE(SUM(CASE WHEN p.id = 5 THEN a.qty ELSE 0 END), 0) AS \"#_ReishiFlaschen\",     -- 003.01 (ID 5)\n    COALESCE(SUM(CASE WHEN p.id = 9 THEN a.qty ELSE 0 END), 0) AS \"#_ShiitakeFlaschen\",   -- SHIITAKE (ID 9)\n    COALESCE(SUM(CASE WHEN p.id = 6 THEN a.qty ELSE 0 END), 0) AS \"#_LionsManeFlaschen\"   -- 005.02 (ID 6)\n    \nFROM sales_order so\n-- Lieferadresse\nLEFT JOIN address ad ON so.party_id = ad.party_id AND ad.type = 'shipping'\n-- Zahlungsart\nLEFT JOIN payment_method pm ON so.payment_method_id = pm.id\n-- Bestellpositionen und Allokationen\nLEFT JOIN sales_order_line sol ON so.id = sol.sales_order_id\nLEFT JOIN sales_order_line_lot_allocation a ON sol.id = a.sales_order_line_id\n-- Produkte (nur aktive)\nLEFT JOIN product p ON a.product_id = p.id AND p.status = 'active'\n\nWHERE so.external_ref = $1\nGROUP BY so.id, ad.id, pm.id",
+    "queryValues": {
+      "values": {
+        "value": "={{ $json.Bestellnummer }}",
+        "string": "={{ $json.Bestellnummer }}"
+      }
+    },
+    "options": {
+      "maxRows": 1
+    },
+    "additionalFields": {}
+  }
+}