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/__init__.py

@@ -0,0 +1,48 @@
+# app/modules/loyalty/__init__.py
+"""
+Loyalty Module - Stamp and points-based loyalty programs.
+
+This module provides:
+- Stamp-based loyalty programs (collect N stamps, get reward)
+- Points-based loyalty programs (earn points per euro spent)
+- Customer loyalty cards with QR codes
+- Staff PIN verification for fraud prevention
+- Google Wallet and Apple Wallet integration
+- Transaction history and analytics
+
+Routes:
+- Admin: /api/v1/admin/loyalty/*
+- Vendor: /api/v1/vendor/loyalty/*
+- Public: /api/v1/loyalty/* (enrollment, wallet passes)
+
+Menu Items:
+- Admin: loyalty-programs, loyalty-analytics
+- Vendor: loyalty, loyalty-cards, loyalty-stats
+
+Usage:
+    from app.modules.loyalty import loyalty_module
+    from app.modules.loyalty.services import program_service, card_service
+    from app.modules.loyalty.models import LoyaltyProgram, LoyaltyCard
+    from app.modules.loyalty.exceptions import LoyaltyException
+"""
+
+# Lazy imports to avoid circular dependencies
+# Routers and module definition are imported on-demand
+
+__all__ = [
+    "loyalty_module",
+    "get_loyalty_module_with_routers",
+]
+
+
+def __getattr__(name: str):
+    """Lazy import to avoid circular dependencies."""
+    if name == "loyalty_module":
+        from app.modules.loyalty.definition import loyalty_module
+
+        return loyalty_module
+    elif name == "get_loyalty_module_with_routers":
+        from app.modules.loyalty.definition import get_loyalty_module_with_routers
+
+        return get_loyalty_module_with_routers
+    raise AttributeError(f"module {__name__!r} has no attribute {name!r}")