feat(host): health endpoints + per-environment appsettings layout

src/Server/ZB.MOM.WW.OtOpcUa.Host/Health/HealthEndpoints.cs

@@ -0,0 +1,41 @@
+using Microsoft.AspNetCore.Builder;
+using Microsoft.AspNetCore.Diagnostics.HealthChecks;
+using Microsoft.AspNetCore.Routing;
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Diagnostics.HealthChecks;
+
+namespace ZB.MOM.WW.OtOpcUa.Host.Health;
+
+public static class HealthEndpoints
+{
+    /// <summary>
+    /// Registers the standard ASP.NET Core health-check infrastructure plus the OtOpcUa-specific
+    /// probes. Mirrors ScadaLink's three-tier pattern: <c>ready</c> = boot ok; <c>active</c> =
+    /// fully serving traffic; <c>healthz</c> = bare process liveness.
+    /// </summary>
+    public static IServiceCollection AddOtOpcUaHealth(this IServiceCollection services)
+    {
+        services.AddHealthChecks()
+            .AddCheck<DatabaseHealthCheck>("configdb", tags: new[] { "ready", "active" })
+            .AddCheck<AkkaClusterHealthCheck>("akka", tags: new[] { "ready", "active" })
+            .AddCheck<AdminRoleLeaderHealthCheck>("admin-leader", tags: new[] { "active" });
+        return services;
+    }
+
+    public static IEndpointRouteBuilder MapOtOpcUaHealth(this IEndpointRouteBuilder app)
+    {
+        app.MapHealthChecks("/health/ready", new HealthCheckOptions
+        {
+            Predicate = c => c.Tags.Contains("ready"),
+        });
+        app.MapHealthChecks("/health/active", new HealthCheckOptions
+        {
+            Predicate = c => c.Tags.Contains("active"),
+        });
+        app.MapHealthChecks("/healthz", new HealthCheckOptions
+        {
+            Predicate = _ => false, // process-liveness only — no probes run.
+        });
+        return app;
+    }
+}