fix: disable rate limiting on /health and /alive endpoints

Health probe endpoints must be exempt from the global rate limiter.
Azure Container App probes hit these paths every 10s as anonymous IP;
without the exemption they hit the 30/min limit after ~5 min and
return 429, causing Azure to mark the container unhealthy and restart it.

Previously only tracing was excluded (line 64-65); rate limiting was not.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: BenjaminMichaelis

EssentialCSharp.Web/Program.cs

@@ -490,11 +490,11 @@ await McpJsonRpcResponseWriter.WriteErrorAsync(
             app.UseForwardedHeaders();
         }
 
-        app.MapHealthChecks("/health");
+        app.MapHealthChecks("/health").DisableRateLimiting();
         app.MapHealthChecks("/alive", new HealthCheckOptions
         {
             Predicate = r => r.Tags.Contains("live")
-        });
+        }).DisableRateLimiting();
 
         if (app.Environment.IsDevelopment())
         {