Fix kubernetes-mcp-server package name: remove incorrect @manusa/ scope

The npm package is published as `kubernetes-mcp-server` (unscoped),
not `@manusa/kubernetes-mcp-server` which returns 404.

apps/harness/Dockerfile

@@ -46,7 +46,7 @@ RUN npm install -g \
     @modelcontextprotocol/server-postgres \
     @modelcontextprotocol/server-filesystem \
     @modelcontextprotocol/server-git \
-    @manusa/kubernetes-mcp-server
+    kubernetes-mcp-server
 
 RUN addgroup --system --gid 1001 nodejs
 RUN adduser --system --uid 1001 nextjs