Default push_desktop.sh to the jakerasp deploy checkout

The remote feed copy now happens by default (overridable with
J621_DESKTOP_FEED_HOST or --host, skippable with --local), so a release is
one command on the build machine.

deploy/push_desktop.sh

@@ -7,23 +7,29 @@
 # has no rsync). electron-updater reads latest-linux.yml / latest.yml from
 # there; the feed URL comes from desktop/electron-builder.yml.
 #
-# Usage: ./push_desktop.sh [--win] [--no-build] [--host user@server:/path]
+# Usage: ./push_desktop.sh [--win] [--no-build] [--local] [--host user@server:/path]
 #   --win       also cross-build the Windows NSIS installer (needs wine)
 #   --no-build  publish what is already in desktop/release/
-#   --host      remote deploy checkout, e.g. jakerasp:/home/jake/servers/J621
+#   --local     only publish locally, skip the remote copy
+#   --host      override the remote deploy checkout
+#
+# The remote copy defaults to $J621_DESKTOP_FEED_HOST, or
+# jakerasp:/home/jake/servers/J621 when that is not set.
 set -euo pipefail
 cd "$(dirname "$0")/.."
 
+DEFAULT_REMOTE="jakerasp:/home/jake/servers/J621"
 BUILD=1
 WIN=0
-REMOTE=""
+REMOTE="${J621_DESKTOP_FEED_HOST:-$DEFAULT_REMOTE}"
 while [ $# -gt 0 ]; do
     case "$1" in
         --win) WIN=1 ;;
         --no-build) BUILD=0 ;;
+        --local) REMOTE="" ;;
         --host) REMOTE="${2:?--host needs user@server:/path}"; shift ;;
         *)
-            echo "usage: $0 [--win] [--no-build] [--host user@server:/path]" >&2
+            echo "usage: $0 [--win] [--no-build] [--local] [--host user@server:/path]" >&2
             exit 2
             ;;
     esac