feat(loyalty): implement complete loyalty module MVP

Add stamp-based and points-based loyalty programs for vendors with:

Database Models (5 tables):
- loyalty_programs: Vendor program configuration
- loyalty_cards: Customer cards with stamp/point balances
- loyalty_transactions: Immutable audit log
- staff_pins: Fraud prevention PINs (bcrypt hashed)
- apple_device_registrations: Apple Wallet push tokens

Services:
- program_service: Program CRUD and statistics
- card_service: Customer enrollment and card lookup
- stamp_service: Stamp operations with anti-fraud checks
- points_service: Points earning and redemption
- pin_service: Staff PIN management with lockout
- wallet_service: Unified wallet abstraction
- google_wallet_service: Google Wallet API integration
- apple_wallet_service: Apple Wallet .pkpass generation

API Routes:
- Admin: /api/v1/admin/loyalty/* (programs list, stats)
- Vendor: /api/v1/vendor/loyalty/* (stamp, points, cards, PINs)
- Public: /api/v1/loyalty/* (enrollment, Apple Web Service)

Anti-Fraud Features:
- Staff PIN verification (configurable per program)
- Cooldown period between stamps (default 15 min)
- Daily stamp limits (default 5/day)
- PIN lockout after failed attempts

Wallet Integration:
- Google Wallet: LoyaltyClass and LoyaltyObject management
- Apple Wallet: .pkpass generation with PKCS#7 signing
- Apple Web Service endpoints for device registration/updates

Also includes:
- Alembic migration for all tables with indexes
- Localization files (en, fr, de, lu)
- Module documentation
- Phase 2 interface and user journey plan

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

app/modules/loyalty/tasks/point_expiration.py

@@ -0,0 +1,41 @@
+# app/modules/loyalty/tasks/point_expiration.py
+"""
+Point expiration task.
+
+Handles expiring points that are older than the configured
+expiration period (future enhancement).
+"""
+
+import logging
+
+from celery import shared_task
+
+logger = logging.getLogger(__name__)
+
+
+@shared_task(name="loyalty.expire_points")
+def expire_points() -> dict:
+    """
+    Expire points that are past their expiration date.
+
+    This is a placeholder for future functionality where points
+    can be configured to expire after a certain period.
+
+    Returns:
+        Summary of expired points
+    """
+    # Future implementation:
+    # 1. Find programs with point expiration enabled
+    # 2. Find cards with points earned before expiration threshold
+    # 3. Calculate points to expire
+    # 4. Create adjustment transactions
+    # 5. Update card balances
+    # 6. Notify customers (optional)
+
+    logger.info("Point expiration task running (no-op for now)")
+
+    return {
+        "status": "success",
+        "cards_processed": 0,
+        "points_expired": 0,
+    }