Ship and run the Go binary instead of Node

Releases now carry one archive per architecture with a static awg-control
binary (services and CLI), the built frontend and .env; the installer no
longer installs Node.js or runs npm.

- tools/release/package.sh: CGO-free builds for linux/amd64 and arm64,
  version injected into `awg-control version`; used by both the GitHub and
  Gitea release workflows
- install.sh: architecture check, per-arch archive, /usr/local/bin/awg-ctrl
  is a symlink to the binary, systemd unit without node in PATH, steps
  renumbered 1/6..6/6
- update from a Node install: the old services are stopped through the old
  CLI, then TS sources, node_modules and the old dist are removed; cli.env,
  panel.id and logs stay
- README: one binary, its roles, architecture requirement

tools/release/package.sh

@@ -0,0 +1,18 @@
+#!/bin/sh
+# package.sh <версия> — архивы релиза: по одному на архитектуру, awgcontrol-<версия>-linux-<arch>.tar.gz.
+# Внутри: awg-control (статический Go-бинарник: сервисы и CLI), awg-ui/dist (фронтенд), .env.
+# Фронтенд должен быть собран заранее (npm run build в awg-ui). Общий для GitHub и Gitea.
+set -eu
+VERSION="$1"
+[ -f awg-ui/dist/index.html ] || { echo "нет awg-ui/dist — сначала npm run build в awg-ui"; exit 1; }
+for ARCH in amd64 arm64; do
+  D="awgcontrol-${VERSION}"
+  rm -rf "$D" && mkdir -p "$D/awg-ui"
+  CGO_ENABLED=0 GOOS=linux GOARCH="$ARCH" go build -trimpath -ldflags "-s -w -X main.version=${VERSION}" \
+    -o "$D/awg-control" ./cmd/awg-control
+  cp -r awg-ui/dist "$D/awg-ui/dist"
+  cp .env "$D/"
+  tar -czf "awgcontrol-${VERSION}-linux-${ARCH}.tar.gz" "$D/"
+  rm -rf "$D"
+  echo "awgcontrol-${VERSION}-linux-${ARCH}.tar.gz"
+done