fix: route all Docker builds through local Nexus mirrors

- All Node Dockerfiles rewritten with NODE_IMAGE + NPM_REGISTRY build args
  defaulting to local Nexus proxies (171.22.25.73:5000/library/node:20-alpine
  and http://mirror:8081/repository/npm-group/)
- Add extra_hosts: mirror:host-gateway to every build section so the
  mirror hostname resolves during docker build
- Replace nuget.org with nuget.docker.config (Nexus mirror) in api/admin-api
  Dockerfiles to fix NuGet restore in Iranian network
- Rewrite admin-web and website Dockerfiles (were referencing non-existent
  meezi-node:20-alpine base image with no npm install step)
- Update dotnet image defaults to 171.22.25.73:5002 MCR proxy in admin-api
  and docker-compose.admin.yml

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

docker/api/Dockerfile

@@ -1,21 +1,18 @@
-# Base images: override via docker-compose build args or .env (see docs/DOCKER.md).
-# Default = Microsoft Container Registry (official). Docker Hub dotnet/* often returns
-# "insufficient_scope" unless logged in, or is unreachable in some regions.
 ARG DOTNET_SDK_IMAGE=mcr.microsoft.com/dotnet/sdk:10.0
 ARG DOTNET_ASPNET_IMAGE=mcr.microsoft.com/dotnet/aspnet:10.0
 
 FROM ${DOTNET_SDK_IMAGE} AS build
 WORKDIR /src
 
-COPY global.json Directory.Build.props Directory.Packages.props nuget.config ./
+COPY global.json Directory.Build.props Directory.Packages.props ./
+# nuget.docker.config points to local Nexus mirror (mirror:8081 via extra_hosts in compose)
+COPY nuget.docker.config ./nuget.config
 
 COPY src/Meezi.Shared/Meezi.Shared.csproj src/Meezi.Shared/
 COPY src/Meezi.Core/Meezi.Core.csproj src/Meezi.Core/
 COPY src/Meezi.Infrastructure/Meezi.Infrastructure.csproj src/Meezi.Infrastructure/
 COPY src/Meezi.API/Meezi.API.csproj src/Meezi.API/
 
-# NuGet over TLS often fails in Docker when VPN/filter/antivirus breaks HTTPS (bad record mac).
-# Retry via nuget.config; offline revocation helps restricted networks. Re-run build if restore fails.
 ENV NUGET_CERT_REVOCATION_MODE=offline
 RUN --mount=type=cache,target=/root/.nuget/packages \
     dotnet restore src/Meezi.API/Meezi.API.csproj --disable-parallel
@@ -28,9 +25,6 @@ RUN dotnet publish src/Meezi.API/Meezi.API.csproj -c Release -o /app/publish /p:
 FROM ${DOTNET_ASPNET_IMAGE} AS runtime
 WORKDIR /app
 
-# No apt-get here — avoids Ubuntu mirror downloads during build (Iran/VPN issues).
-# Healthcheck uses a TCP probe (see docker-compose.yml).
-
 ENV ASPNETCORE_URLS=http://+:8080
 EXPOSE 8080