Route all package mirrors through local Nexus

Point Docker, NuGet, and npm pulls at the Nexus group repos on
171.22.25.73:8081 for both CI/CD and local builds, so the pipeline and
developers no longer depend on Docker Hub, MCR, nuget.org, or npmjs.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

docker/daemon-registry-mirror.example.json

@@ -1,6 +1,8 @@
 {
+  "insecure-registries": [
+    "171.22.25.73:8081"
+  ],
   "registry-mirrors": [
-    "https://docker.iranrepo.ir",
-    "https://registry.docker.ir"
+    "http://171.22.25.73:8081"
   ]
 }