fix: restore clock and validation contracts

src/KArtSell.Host/Features/Portfolio/VS08_DashboardEndpoint.cs

@@ -208,11 +208,11 @@ public class DashboardService : IDashboardService
                 a.Message)).ToList(),
             HealthScore = healthScore,
             RiskInsights = riskInsights,
-            LastUpdate = _clock.UtcNow.DateTime,
+            LastUpdate = _clock.UtcNow.UtcDateTime,
         };
 
         // Cache result
-        _cache[portfolioId] = (_clock.UtcNow, response);
+        _cache[portfolioId] = (_clock.UtcNow.UtcDateTime, response);
 
         return response;
     }

src/KArtSell.Host/Program.cs

@@ -143,11 +143,13 @@ builder.Services.AddScoped<KArtSell.Host.Features.MarketData.IMarketDataIngestio
 builder.Services.AddScoped<KArtSell.Host.Features.Portfolio.IPortfolioRebalanceService>(sp =>
     new KArtSell.Host.Features.Portfolio.PortfolioRebalanceService(
         sp.GetRequiredService<NpgsqlDataSource>(),
-        sp.GetRequiredService<IBackgroundJobClient>()));
+        sp.GetRequiredService<IBackgroundJobClient>(),
+        sp.GetRequiredService<IClock>()));
 
 builder.Services.AddScoped<KArtSell.Host.Features.Portfolio.IRiskMetricsService>(sp =>
     new KArtSell.Host.Features.Portfolio.RiskMetricsService(
-        sp.GetRequiredService<NpgsqlDataSource>()));
+        sp.GetRequiredService<NpgsqlDataSource>(),
+        sp.GetRequiredService<IClock>()));
 
 // Risk & Stress (VS-06~07)
 builder.Services.AddScoped<KArtSell.Host.Features.Portfolio.IStressTestService>(sp =>
@@ -162,7 +164,8 @@ builder.Services.AddScoped<KArtSell.Host.Features.Portfolio.IAlertService>(sp =>
 // Dashboard (VS-08)
 builder.Services.AddScoped<KArtSell.Host.Features.Portfolio.IDashboardService>(sp =>
     new KArtSell.Host.Features.Portfolio.DashboardService(
-        sp.GetRequiredService<NpgsqlDataSource>()));
+        sp.GetRequiredService<NpgsqlDataSource>(),
+        sp.GetRequiredService<IClock>()));
 
 // Security Master (VS-02) - Temporarily disabled: ISecurityMasterRulesStore implementation pending
 // builder.Services.AddScoped<KArtSell.Host.Features.SecurityMaster.ISecurityMasterSyncHandler>(sp =>

src/KArtSell.Modules.ModelOperations/Domain/VS08_DashboardPolicy.cs

@@ -3,7 +3,7 @@ namespace KArtSell.Modules.ModelOperations.Domain;
 /// <summary>
 /// VS-08 DOMAIN: Dashboard aggregation policy
 /// Pure business logic for combining portfolio, risk metrics, stress, alerts into unified snapshot
-/// No I/O, no DateTime.Now (all times injected)
+/// No I/O; time-dependent values are supplied by callers.
 /// </summary>
 
 // Note: This policy combines results from VS-04~07 components