Prevent duplicate manufacturer parties

docs/architektur/database/module_db_ownership.md

@@ -11,6 +11,7 @@ Diese Referenz ordnet die aktuellen Tabellen, Views und technischen DB-Artefakte
 ### `kontakte`
 
 - `party`
+- `party_role`
 - `address`
 - `contact`
 - `party_external_identity`

docs/modules/erp/kontakte/README.md

@@ -14,6 +14,7 @@ Zentraler Kontaktstamm fuer Kunden, Lieferanten und sonstige Parteien.
 ## Writes
 
 - Kontaktstamm
+- Herstellerrollen im Parteien-Stamm
 - Adressen
 - Kommunikationsdaten
 

modules/erp/kontakte/service.php

@@ -138,7 +138,6 @@ function create_manufacturer(PDO $pdo, string $name, ?string $email = null, ?str
     $existingStmt = $pdo->prepare(
         "SELECT p.id, p.name, p.email, p.phone
          FROM party p
-         INNER JOIN party_role pr ON pr.party_id = p.id AND pr.role_code = 'manufacturer'
          WHERE LOWER(TRIM(p.name)) = LOWER(:name)
          LIMIT 1
          FOR UPDATE"
@@ -146,6 +145,11 @@ function create_manufacturer(PDO $pdo, string $name, ?string $email = null, ?str
     $existingStmt->execute([':name' => $name]);
     $existing = $existingStmt->fetch();
     if (is_array($existing)) {
+        $roleStmt = $pdo->prepare(
+            "INSERT INTO party_role (party_id, role_code) VALUES (:party_id, 'manufacturer')
+             ON CONFLICT (party_id, role_code) DO NOTHING"
+        );
+        $roleStmt->execute([':party_id' => (int) $existing['id']]);
         return [
             'id' => (int) $existing['id'],
             'name' => (string) $existing['name'],