Add Rider launch profiles, fix DI and migrations for dev startup

- Rider launch profiles: "ScadaLink Central" and "ScadaLink Site"
- appsettings.Central.json: correct test_infra credentials (ScadaLink_Dev1#,
  scadalink_app user, GLAuth on 3893, Mailpit on 1025)
- Fix HealthMonitoring DI: split site vs central registration to avoid
  missing IHealthReportTransport on central
- Regenerate single clean EF migration (InitialSchema) covering all entities
- Suppress PendingModelChangesWarning in dev mode
- Fix isDevelopment check for ASPNETCORE_ENVIRONMENT propagation

Verified: Host starts, connects to SQL Server, applies migrations, boots
Akka.NET cluster, LDAP auth works (admin/password via GLAuth), health
endpoint returns Healthy.

src/ScadaLink.Host/Program.cs

@@ -65,6 +65,7 @@ try
         builder.Services.AddClusterInfrastructure();
         builder.Services.AddCommunication();
         builder.Services.AddHealthMonitoring();
+        builder.Services.AddCentralHealthAggregation();
         builder.Services.AddExternalSystemGateway();
         builder.Services.AddNotificationService();
 
@@ -98,7 +99,8 @@ try
         // Apply or validate database migrations (skip when running in test harness)
         if (!string.Equals(configuration["ScadaLink:Database:SkipMigrations"], "true", StringComparison.OrdinalIgnoreCase))
         {
-            var isDevelopment = app.Environment.IsDevelopment();
+            var isDevelopment = app.Environment.IsDevelopment()
+                || string.Equals(Environment.GetEnvironmentVariable("ASPNETCORE_ENVIRONMENT"), "Development", StringComparison.OrdinalIgnoreCase);
             using (var scope = app.Services.CreateScope())
             {
                 var dbContext = scope.ServiceProvider.GetRequiredService<ScadaLinkDbContext>();