chore: force backend Docker cache bust for deploy

backend/Controllers/HealthController.cs

@@ -34,20 +34,25 @@ public class HealthController(IAgentRuntime runtime, HealthCheckService healthCh
             runtimeDetail = ex.Message;
         }
 
+        static IReadOnlyDictionary<string, object?> NormalizeData(IReadOnlyDictionary<string, object> source)
+        {
+            return source.ToDictionary(kvp => kvp.Key, kvp => (object?)kvp.Value);
+        }
+
         var entries = report.Entries.ToDictionary(
             e => e.Key,
             e => new
             {
                 status = e.Value.Status.ToString(),
                 description = e.Value.Description,
-                data = (IReadOnlyDictionary<string, object?>)e.Value.Data
+                data = NormalizeData(e.Value.Data)
             });
 
         entries["runtime"] = new
         {
             status = runtimeStatus,
             description = runtimeDetail,
-            data = (IReadOnlyDictionary<string, object?>)new Dictionary<string, object?>()
+            data = new Dictionary<string, object?>() as IReadOnlyDictionary<string, object?>
         };
 
         var isHealthy = report.Status == HealthStatus.Healthy && runtimeStatus == "Online";

backend/Dockerfile

@@ -1,6 +1,7 @@
 FROM mcr.microsoft.com/dotnet/sdk:10.0-alpine AS build
 WORKDIR /src
 COPY Nexus.Api.csproj .
+# cache-bust: 2026-06-22T19:56+02
 RUN dotnet restore
 COPY . .
 RUN dotnet publish -c Release -o /app/publish