awg-ctrl: update, reinstall and uninstall from the menu

The awg-ctrl menu only started, stopped and changed the panel login; updating
or removing an installation meant finding and running install.sh by hand. The
menu gets "Обновить", "Переустановить" and "Удалить" (7–9), and the same as
`awg-ctrl update | reinstall | uninstall`.

The work stays in install.sh, which now takes ACTION=update|reinstall|uninstall
to skip its own menu. The CLI fetches it — the latest from INSTALLER_URL
(GitHub by default) for update and reinstall, the copy shipped in the release
archive for uninstall, so removal works offline — writes it to a temp file and
execs bash on it in the same terminal. It must not run from /opt/awg-control or
via `bash -c`: kill_related kills every process whose command line holds the
install path, and would kill the installer itself. The CLI passes its original
environment, not the one with cli.env loaded, or the installer would take
UI_PORT, SERVER_NAME and the rest as explicit overrides. The installer deletes
its temp copy on start.

The release archive now includes install.sh.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_013bNGYiDst62wH3ZGTRPFLJ

tools/release/package.sh

@@ -1,6 +1,7 @@
 #!/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.
+# Внутри: awg-control (статический Go-бинарник: сервисы и CLI), awg-ui/dist (фронтенд), .env и
+# install.sh (им `awg-ctrl uninstall` удаляет установку без сети).
 # Фронтенд должен быть собран заранее (npm run build в awg-ui). Общий для GitHub и Gitea.
 set -eu
 VERSION="$1"
@@ -11,7 +12,7 @@ for ARCH in amd64 arm64; do
   CGO_ENABLED=0 GOOS=linux GOARCH="$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/"
+  cp .env install.sh "$D/"
   tar -czf "awgcontrol-${VERSION}-linux-${ARCH}.tar.gz" "$D/"
   rm -rf "$D"
   echo "awgcontrol-${VERSION}-linux-${ARCH}.tar.gz"