OPS-1: Dockerfiles (net10 API + nginx frontend) + production config

- GerbilManagerWebAPI/Dockerfile: net7->net10 multi-stage; build context=repo
  root (includes ServiceDefaults); port 8080 (.NET 10 container default)
- gerbil-manager-web/Dockerfile: drop VITE_API_BASE_URL build-arg; nginx proxies
  /api/* to api:8080 (strip prefix), /scalar, /openapi/ -- one published port 80
- gerbil-manager-web/src/api/client.ts: default API_BASE_URL /api (relative),
  no hostname coupling at build time; Aspire still injects absolute LAN URL in dev
- GerbilManagerWebAPI/Program.cs: run EF Migrate() at startup always (not Dev-only)
- GerbilManager.ServiceDefaults/Extensions.cs: expose /health + /alive in all
  environments (compose healthcheck requires them in Production)

Co-Authored-By: Claude Sonnet 4.6 (1M context) <noreply@anthropic.com>

GerbilManager.ServiceDefaults/Extensions.cs

@@ -108,19 +108,13 @@ public static class Extensions
 
     public static WebApplication MapDefaultEndpoints(this WebApplication app)
     {
-        // Adding health checks endpoints to applications in non-development environments has security implications.
-        // See https://aka.ms/aspire/healthchecks for details before enabling these endpoints in non-development environments.
-        if (app.Environment.IsDevelopment())
+        // Health checks always exposed — compose healthchecks and Aspire both rely on them.
+        // Trusted home LAN only (no public exposure, no auth — see board constraint).
+        app.MapHealthChecks(HealthEndpointPath);
+        app.MapHealthChecks(AlivenessEndpointPath, new HealthCheckOptions
         {
-            // All health checks must pass for app to be considered ready to accept traffic after starting
-            app.MapHealthChecks(HealthEndpointPath);
-
-            // Only health checks tagged with the "live" tag must pass for app to be considered alive
-            app.MapHealthChecks(AlivenessEndpointPath, new HealthCheckOptions
-            {
-                Predicate = r => r.Tags.Contains("live")
-            });
-        }
+            Predicate = r => r.Tags.Contains("live")
+        });
 
         return app;
     }