fix: package-based compliance audit — feature DIFF, remove hardcoded fallbacks

- ActivateClubMembership: replace GetAllFeatureIds with PackageFeature DIFF (Q20)
- ActivateClubMembership: fix re-activation early return — check current cycle
- AcceptClubMembershipContract: same feature DIFF logic
- VerifyPackagePurchase: remove ?? 2.0m fallback, throw if package null
- PackageService: remove ?? 2.0m fallback for DiscountMultiplier
- UserOrderService: remove ?? 1B fallback for MagicWalletMaxDeposit
- SystemConstants: remove 9 dead [Obsolete] constants (per-package values)

src/CMSMicroservice.Application/ClubMembershipCQ/Commands/AcceptClubMembershipContract/AcceptClubMembershipContractCommandHandler.cs

@@ -262,36 +262,8 @@ public class AcceptClubMembershipContractCommandHandler
 
         await _context.SaveChangesAsync(cancellationToken);
 
-        // 10. اعطای ویژگی‌های باشگاه برای کاربر (فقط برای عضویت جدید)
-        if (isNewMembership)
-        {
-            var featureIds = ClubFeatureTypeExtensions.GetAllFeatureIds();
-            var clubFeatures = await _context.ClubFeatures
-                .Where(f => !f.IsDeleted && featureIds.Contains(f.Id))
-                .ToListAsync(cancellationToken);
-
-            if (clubFeatures.Any())
-            {
-                var userClubFeatures = clubFeatures.Select(feature => new UserClubFeature
-                {
-                    UserId = user.Id,
-                    ClubMembershipId = clubMembership.Id,
-                    ClubFeatureId = feature.Id,
-                    GrantedAt = activationDate,
-                    IsActive = true,
-                    Notes = "اعطا شده هنگام امضای قرارداد"
-                }).ToList();
-
-                _context.UserClubFeatures.AddRange(userClubFeatures);
-                await _context.SaveChangesAsync(cancellationToken);
-
-                _logger.LogInformation(
-                    "Granted {Count} club features to UserId {UserId}",
-                    clubFeatures.Count,
-                    user.Id
-                );
-            }
-        }
+        // 10. اعمال ویژگی‌های پکیج — DIFF/تفاضل (Q20)
+        await ApplyFeatureDiffAsync(user.Id, clubMembership.Id, package.Id, isNewMembership, activationDate, cancellationToken);
 
         _logger.LogInformation(
             "Club membership contract accepted and activated for UserId: {UserId}, ContractId: {ContractId}, MembershipId: {MembershipId}",
@@ -321,6 +293,61 @@ public class AcceptClubMembershipContractCommandHandler
         return week.Id;
     }
 
+    private async Task ApplyFeatureDiffAsync(
+        long userId, long membershipId, long packageId,
+        bool isNewMembership, DateTime activationDate,
+        CancellationToken cancellationToken)
+    {
+        var newFeatureIds = await _context.PackageFeatures
+            .Where(pf => pf.PackageId == packageId && pf.IsIncluded && !pf.IsDeleted)
+            .Select(pf => pf.ClubFeatureId)
+            .ToListAsync(cancellationToken);
+
+        if (!newFeatureIds.Any())
+        {
+            _logger.LogWarning("No PackageFeatures for PackageId {PackageId}", packageId);
+            return;
+        }
+
+        var currentFeatures = await _context.UserClubFeatures
+            .Where(ucf => ucf.UserId == userId && ucf.IsActive)
+            .ToListAsync(cancellationToken);
+
+        var currentFeatureIds = currentFeatures.Select(f => f.ClubFeatureId).ToHashSet();
+        var toAdd = newFeatureIds.Where(id => !currentFeatureIds.Contains(id)).ToList();
+        var toRemove = currentFeatures.Where(f => !newFeatureIds.Contains(f.ClubFeatureId)).ToList();
+
+        foreach (var feature in toRemove)
+        {
+            feature.IsActive = false;
+            feature.Notes = $"حذف شده بابت تغییر پکیج (PackageId: {packageId})";
+        }
+
+        if (toAdd.Any())
+        {
+            var newUserFeatures = toAdd.Select(featureId => new UserClubFeature
+            {
+                UserId = userId,
+                ClubMembershipId = membershipId,
+                ClubFeatureId = featureId,
+                GrantedAt = activationDate,
+                IsActive = true,
+                Notes = isNewMembership
+                    ? "اعطا شده هنگام امضای قرارداد"
+                    : $"اضافه شده بابت خرید مجدد پکیج (PackageId: {packageId})"
+            }).ToList();
+
+            _context.UserClubFeatures.AddRange(newUserFeatures);
+        }
+
+        await _context.SaveChangesAsync(cancellationToken);
+
+        _logger.LogInformation(
+            "Feature DIFF applied for UserId={UserId}: Added={Added}, Removed={Removed}, Kept={Kept}",
+            userId, toAdd.Count, toRemove.Count,
+            currentFeatureIds.Count - toRemove.Count);
+    }
+
     private async Task<(bool Success, string Message)> VerifyOtpAsync(
         string mobile,
         string code,