Make GOPROXY a build arg (proxy.golang.org is blocked on some networks)

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

deploy/redeploy-tefter.sh

@@ -6,8 +6,10 @@ SERVICE=tefter.service
 
 cd "$APP_DIR"
 
-# Port the app is published on (kept in .env.docker next to the compose file).
-WEB_PORT=$(grep -oP '^WEB_PORT=\K.*' .env.docker 2>/dev/null || echo 8420)
+# Host-specific settings (WEB_PORT, GOPROXY, ...) live in .env.docker next to
+# the compose file; export them so compose interpolation sees them.
+set -a; [ -f .env.docker ] && . ./.env.docker; set +a
+WEB_PORT=${WEB_PORT:-8420}
 
 echo "==> Pulling latest code..."
 git pull