feat(api): add BNPL, ERP, WhatsApp Cloud, Supplier Portal stubs

- bnpl_bp.py: APLAZO/Kueski/Clip application workflow (mock)
- erp_bp.py: Aspel/CONTPAQi/SAP/Odoo sync jobs (mock)
- whatsapp_cloud_bp.py: Meta Cloud API webhook, messages, templates
- supplier_portal_bp.py: demand by zone/branch and top-parts analytics
- app.py: register all new blueprints

pos/blueprints/whatsapp_cloud_bp.py

@@ -0,0 +1,86 @@
+"""WhatsApp Business API (Meta Cloud) Blueprint.
+
+Replaces Baileys webhook for scalable production messaging.
+Stubs ready for Meta Cloud API credentials.
+"""
+from flask import Blueprint, request, jsonify, g
+from functools import wraps
+import uuid
+from datetime import datetime
+
+whatsapp_cloud_bp = Blueprint('whatsapp_cloud', __name__, url_prefix='/pos/api/whatsapp-cloud')
+
+
+from middleware import require_auth
+
+
+_mock_messages = {}
+
+
+@whatsapp_cloud_bp.route('/webhook', methods=['GET', 'POST'])
+def webhook():
+    """Meta Cloud API webhook verification and message reception."""
+    if request.method == 'GET':
+        # Verification challenge
+        mode = request.args.get('hub.mode')
+        token = request.args.get('hub.verify_token')
+        challenge = request.args.get('hub.challenge')
+        # In production: verify token against configured VERIFY_TOKEN
+        if mode == 'subscribe' and challenge:
+            return challenge, 200
+        return jsonify({'error': 'Verification failed'}), 403
+
+    # POST — incoming messages
+    data = request.get_json() or {}
+    # In production: process entries, messages, statuses
+    return jsonify({'received': True, 'entries': len(data.get('entry', []))}), 200
+
+
+@whatsapp_cloud_bp.route('/messages', methods=['POST'])
+@require_auth()
+def send_message():
+    """Send a message via Meta Cloud API."""
+    data = request.get_json() or {}
+    to = data.get('to')
+    body = data.get('body')
+    template = data.get('template')
+
+    if not to or (not body and not template):
+        return jsonify({'error': 'to and body/template are required'}), 400
+
+    msg_id = str(uuid.uuid4())
+    _mock_messages[msg_id] = {
+        'id': msg_id,
+        'to': to,
+        'body': body,
+        'template': template,
+        'status': 'sent',
+        'sent_at': datetime.utcnow().isoformat(),
+    }
+    return jsonify(_mock_messages[msg_id]), 201
+
+
+@whatsapp_cloud_bp.route('/templates', methods=['GET'])
+@require_auth()
+def list_templates():
+    """List approved message templates."""
+    return jsonify({
+        'templates': [
+            {'name': 'order_ready', 'language': 'es_MX', 'category': 'UTILITY', 'status': 'APPROVED'},
+            {'name': 'payment_reminder', 'language': 'es_MX', 'category': 'UTILITY', 'status': 'APPROVED'},
+            {'name': 'welcome_message', 'language': 'es_MX', 'category': 'MARKETING', 'status': 'PENDING'},
+        ]
+    })
+
+
+@whatsapp_cloud_bp.route('/status', methods=['GET'])
+@require_auth()
+def get_status():
+    """Check Meta Cloud API connection status."""
+    return jsonify({
+        'connected': False,
+        'phone_number_id': None,
+        'business_account_id': None,
+        'message_limit': None,
+        'note': 'Configure WHATSAPP_CLOUD_ACCESS_TOKEN and PHONE_NUMBER_ID to connect',
+    })