feat(loyalty): production readiness round 2 — 12 security, integrity & correctness fixes

Security:
- Fix TOCTOU race conditions: move balance/limit checks after row lock in redeem_points, add_stamp, redeem_stamps
- Add PIN ownership verification to update/delete/unlock store routes
- Gate adjust_points endpoint to merchant_owner role only

Data integrity:
- Track total_points_voided in void_points
- Add order_reference idempotency guard in earn_points

Correctness:
- Fix LoyaltyProgramAlreadyExistsException to use merchant_id parameter
- Add StorefrontProgramResponse excluding wallet IDs from public API
- Add bounds (±100000) to PointsAdjustRequest.points_delta

Audit & config:
- Add CARD_REACTIVATED transaction type with audit record
- Improve admin audit logging with actor identity and old values
- Use merchant-specific PIN lockout settings with global fallback
- Guard MerchantLoyaltySettings creation with get_or_create pattern

Tests: 27 new tests (265 total) covering all 12 items — unit and integration.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

app/modules/loyalty/schemas/program.py

@@ -227,6 +227,16 @@ class ProgramResponse(BaseModel):
     total_points_redeemed: int | None = None
 
 
+class StorefrontProgramResponse(ProgramResponse):
+    """Program response for unauthenticated storefront visitors — excludes wallet integration IDs."""
+
+    model_config = ConfigDict(from_attributes=True)
+
+    google_issuer_id: None = Field(None, exclude=True)
+    google_class_id: None = Field(None, exclude=True)
+    apple_pass_type_id: None = Field(None, exclude=True)
+
+
 class ProgramListResponse(BaseModel):
     """Schema for listing loyalty programs (admin)."""