CI/Docker: use SSL-free Nexus endpoints (mirror serves partial chain)

The HTTPS Nexus serves an incomplete cert chain that container trust stores
reject (NU1301 PartialChain / UNABLE_TO_GET_ISSUER), failing CI restore/install.
- NuGet has no strict-ssl flag → point CI + Dockerfile + compose at the plain-HTTP
  Nexus (http://171.22.25.73:8081, allowInsecureConnections) — no TLS, no cert check.
- npm: add --strict-ssl=false to the CI web-check install (Dockerfile already had it);
  Docker npm registry default also moved to the HTTP Nexus.
- ENV_FILE.example documents NUGET_INDEX/NPM_REGISTRY overrides.

Local dev (Windows trusts the cert) + image base pulls (Docker trusts it) are
unaffected — only in-container package feeds switch to HTTP.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Dockerfile

@@ -11,7 +11,7 @@ COPY package*.json ./
 # NPM_REGISTRY=http://<nexus-ip>:8081/repository/npm-group/ for hosts whose trust
 # store lacks the mirror's intermediate (PartialChain) — e.g. local Docker Desktop.
 # strict-ssl=false also tolerates the partial chain when HTTPS is used.
-ARG NPM_REGISTRY=https://mirror.soroushasadi.com/repository/npm-group/
+ARG NPM_REGISTRY=http://171.22.25.73:8081/repository/npm-group/
 RUN npm ci --legacy-peer-deps --strict-ssl=false --no-audit --no-fund \
       --registry "${NPM_REGISTRY}"
 COPY . .