环境选择菜单始终显示，.ctms-env 配置作为默认选中项

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

install.sh

@@ -170,15 +170,12 @@ ctms_config_get() {
 }
 
 pick_env() {
-  local env
+  local env default_index=0
   env="$(ctms_config_get "env" || true)"
-  if [[ -n "$env" ]]; then
+  case "$env" in
-    ctms_require_env "$env"
+    main)    default_index=1 ;;
-    SELECTED_ENV="$env"
+    release) default_index=2 ;;
-    ctms_info "部署环境: ${C_BOLD}${env}${C_RESET}（来自 .ctms-env）"
+  esac
-    return
-  fi
-  local default_index=0
   select_menu "选择环境" "$default_index" \
     "dev       本地开发环境      Vite 热加载 / 默认密钥" \
     "main      内网测试环境      预发布验证 / 生产模式" \