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/Properties/launchSettings.json

@@ -0,0 +1,24 @@
+{
+  "profiles": {
+    "ScadaLink Central": {
+      "commandName": "Project",
+      "dotnetRunMessages": true,
+      "launchBrowser": true,
+      "launchUrl": "",
+      "applicationUrl": "https://localhost:5001;http://localhost:5000",
+      "environmentVariables": {
+        "DOTNET_ENVIRONMENT": "Central",
+        "ASPNETCORE_ENVIRONMENT": "Development"
+      }
+    },
+    "ScadaLink Site": {
+      "commandName": "Project",
+      "dotnetRunMessages": true,
+      "launchBrowser": false,
+      "environmentVariables": {
+        "DOTNET_ENVIRONMENT": "Site",
+        "ASPNETCORE_ENVIRONMENT": "Development"
+      }
+    }
+  }
+}