feat(workshop): make brand/model required, plate optional, remove VIN

- create_vehicle endpoints now require make and model; plate is optional; VIN is no longer stored.

- Updated new-vehicle modal: removed VIN field, plate is optional, brand/model marked required.

pos/blueprints/service_order_bp.py

@@ -415,11 +415,12 @@ def create_customer_for_workshop():
 def create_vehicle_for_workshop():
     """Create a fleet vehicle directly from the workshop flow.
 
-    Vehicles must be assigned to a customer.
+    Vehicles must be assigned to a customer. Brand and model are required;
+    plate is optional and VIN is not used.
     """
     data = request.get_json() or {}
-    if not data.get('plate') and not data.get('vin'):
-        return jsonify({'error': 'Se requiere placa o VIN'}), 400
+    if not data.get('make') or not data.get('model'):
+        return jsonify({'error': 'Marca y modelo son obligatorios'}), 400
     if not data.get('customer_id'):
         return jsonify({'error': 'El vehiculo debe estar asignado a un cliente'}), 400
 
@@ -434,12 +435,12 @@ def create_vehicle_for_workshop():
 
         cur.execute("""
             INSERT INTO fleet_vehicles
-                (branch_id, customer_id, plate, vin, make, model, year,
+                (branch_id, customer_id, plate, make, model, year,
                  current_mileage, fuel_type, color, owner_name, notes)
-            VALUES (%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s)
+            VALUES (%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s)
             RETURNING id
         """, (
-            data.get('branch_id', g.branch_id), data['customer_id'], data.get('plate'), data.get('vin'),
+            data.get('branch_id', g.branch_id), data['customer_id'], data.get('plate'),
             data.get('make'), data.get('model'), data.get('year'),
             data.get('current_mileage', 0), data.get('fuel_type', 'gasolina'),
             data.get('color'), cust[0], data.get('notes'),