Fix date range filtering to refresh data when dates change

- Use date range as seed for Random to generate varying data
- Scale transaction counts and values based on date range length
- Consistent implementation in both TestMediatorService and ReportingRequestHandler
- Now changing dates will show different transaction volumes

Co-authored-by: StuartFerguson <16325469+StuartFerguson@users.noreply.github.com>

Author: Copilot

EstateManagementUI.BlazorServer/Services/TestMediatorService.cs

@@ -580,7 +580,13 @@ private List<MerchantTransactionSummaryModel> GetMockMerchantTransactionSummary(
     private List<ProductPerformanceModel> GetMockProductPerformance(Queries.GetProductPerformanceQuery query)
     {
         var contracts = _testDataStore.GetContracts(query.EstateId);
-        var random = new Random(42); // Use seed for consistent data
+        
+        // Calculate days in the date range to vary data based on period
+        var daysInRange = (query.EndDate - query.StartDate).Days + 1;
+        
+        // Use date range as seed for consistent but varying data
+        var seed = query.StartDate.GetHashCode() ^ query.EndDate.GetHashCode();
+        var random = new Random(seed);
 
         // Collect all unique products from all contracts
         var productNames = contracts
@@ -594,10 +600,14 @@ private List<ProductPerformanceModel> GetMockProductPerformance(Queries.GetProdu
         decimal totalValue = 0;
 
         // Generate mock transaction data for each product
+        // Scale transaction counts based on the date range length
+        var countMultiplier = Math.Max(1, daysInRange / 30.0); // Scale based on 30-day baseline
+        
         foreach (var productName in productNames)
         {
-            var transactionCount = random.Next(50, 500);
-            var transactionValue = Math.Round((decimal)(random.NextDouble() * 30000 + 5000), 2);
+            var baseTransactionCount = random.Next(50, 500);
+            var transactionCount = (int)(baseTransactionCount * countMultiplier);
+            var transactionValue = Math.Round((decimal)(random.NextDouble() * 30000 + 5000) * (decimal)countMultiplier, 2);
             totalValue += transactionValue;
 
             products.Add(new ProductPerformanceModel

EstateManagementUI.BusinessLogic/RequestHandlers/ReportingRequestHandler.cs

@@ -179,7 +179,13 @@ public async Task<Result<List<ProductPerformanceModel>>> Handle(GetProductPerfor
         }
 
         var products = new List<ProductPerformanceModel>();
-        var random = new Random(42); // Use seed for consistent test data
+        
+        // Calculate days in the date range to vary data based on period
+        var daysInRange = (request.EndDate - request.StartDate).Days + 1;
+        
+        // Use date range as seed for consistent but varying data
+        var seed = request.StartDate.GetHashCode() ^ request.EndDate.GetHashCode();
+        var random = new Random(seed);
 
         // Collect all unique products from all contracts
         var productNames = contracts.Data
@@ -191,11 +197,15 @@ public async Task<Result<List<ProductPerformanceModel>>> Handle(GetProductPerfor
         decimal totalValue = 0;
 
         // Generate mock transaction data for each product
+        // Scale transaction counts based on the date range length
+        var countMultiplier = Math.Max(1, daysInRange / 30.0); // Scale based on 30-day baseline
+        
         foreach (var productName in productNames) {
             if (string.IsNullOrEmpty(productName)) continue;
 
-            var transactionCount = random.Next(50, 500);
-            var transactionValue = Math.Round((decimal)(random.NextDouble() * 30000 + 5000), 2);
+            var baseTransactionCount = random.Next(50, 500);
+            var transactionCount = (int)(baseTransactionCount * countMultiplier);
+            var transactionValue = Math.Round((decimal)(random.NextDouble() * 30000 + 5000) * (decimal)countMultiplier, 2);
             totalValue += transactionValue;
 
             products.Add(new ProductPerformanceModel {